Nice, @christravelblog! Last year I also did a partial road trip of Czechia (my absolute first time in the country) and of course it resembles yours somewhat: that string of WHS in Southern Bohemia already sets an itinerary by itself!
I was around for 17(+2) days in total, of which 10 by rented car. I am posting the scheme of the itinerary here with some personal or practical comments on the single places and attractions based on my experience; I don't know if this may help or inspire you. Anyway, doing the count I managed a grand total of... 8 WHSs and 2 TWHSs!!! I know, I have the impression that my pace might resemble that of a snail compared to that of other members. :-D At the time, I wasn't also aware of some TWHSs. Anyway, also with regard to pace and feasibility, I'll put something in the comments... As a general consideration, Czechia may not be huge, but neither is it so small: I think also also that the slightly decentrated position of Prague, one of the most likely starting and ending points for visitors, makes visiting both the regions west to it and those east to it more dispersive than maybe at first glance.
Here is my itinerary of August 2020, flying from Italy (if I were as good as meltwaterfalls, I'd do a map):
- Day 1
Late arrival in Prague
- Days 2-5
Visit of the city. Starting on the first day with the Hrad (castle) and surrounding, then the Jewish neighbourhood, then I hopelessly got absorbed by all the excellent art museums, and, and... Prague needs no presentation, but for me this was a short stay, I had to be very selective and I regret having had to cut one/two days because of last-minute summer holidays' rescheduling. This made me a little nervous and I also really only appreciated the city in hindsight. Anyway, I know I have left lots of things for a revisit!!!
*Question for the locals: when I was there, many museums were closed for restoration works, in particular the city and the communism museum, which were on my wish list. Would you recommend them?
- Day 6 [car]
I got the car and bolted (ca 1:30 through secondary roads: Prague > Kolín > Týnec nad Labem > Kladruby, and passing from Selmice I could already appreciate the horsescape) to Kladruby nad Labem, where I took all the tours. In the late afternoon I reached Kutná Hora (half an hour drive) and went for a walk.
*Note: especially on weekends, it can get really crowded. It is popular! It was a Sunday and it was a mess. I booked the tours nearly a week in advance and places were already disappearing.
*Comment: You can manage to link all the tours together, it will take some 3-4 hours. However, the must is the tour of the stables, the others can be disappointing. Book them in advance! They are in Czech, you will be given material to exercise your speed reading skills :-P
- Day 7 [car]
Visit of Kutná Hora and Sedlec (I fully agree with Matejicek's review). It was a Monday, so unfortunately the main museum about the mines, where you can also go in the underground, was closed.
In the evening I reached (longer than due, I got lost in the tentacular junctions of the great Prague...) the intermediate Mníšek pod Brdy (south of Prague... nice zámek) for the night.
- Day 8 [car]
Visit of Koněprusy's caves in the morning. Then transfer (less than an hour, very windy roads and enchanting sceneries along the small rivers) to Karlštejn's castle, where I took the two big tours. Finally, evening drive and late arrival in Vimperk (south-west near the border, 128kms, ca. 2 hours).
*Comment: I agree with the other posters that the castle, while impressive and scenic in its own right, is only worth the detour if you take at least one tour, the king of which is number 2 to the paradise chapel. And beware that it is a whopping 2 hours, 30+ tour! And totally worth it.
*Note: you normally have to book the tours with a minimum advance, and they are at fixed hours during the day, especially not-Czech ones. But surprisingly, as I learnt, for a foreigner this might result easier, because the huge request is from locals: you should be able to just come and book one... but don't risk it. By the way, it happened that I was the only one at the guided tour 16-18, and so saw the chapel all for myself at the golden hour. Unforgettable!
- Day 9 [car]
Short visit of Vimperk, then not completely satisfying hike in the Šumava (Bohemian forest) from Kvilda. Evening transfer to Český Krumlov (1:30-2, with scenic detour to Frymburk along the lakes).
- Day 10-11 [car]
Visit of Český Krumlov.
*Comment: Here I probably spent a day too much, but I needed a stop. The castle, its garden and the center can all be enjoyed in a single, full day (you can chain the 3 available, obligatory guided tours: not to miss the one with the ballroom). I can recommend the small raft tour on the river, as touristy as it may be. Going to Zlatá Koruna by canoe would be even better, but being unexperienced & alone I had to renounce. Anyway, the town has many interesting things to offer! Photoatelier Seidel was nice.
- Day 12 [car]
Morning visit to the monastery complex of Zlatá Koruna (0:10), a minor but interesting site. Then Holašovice (good 0:30 on very minor roads)! It's not that difficult to reach, but it is really only signposted in its immediate proximities. Then onwards to Třeboň, bypassing České Budějovice (less than an hour).
*Comment: Well, in Holašovice you really can only take a short walk around. Then, there's this Holašovice's Stonehenge where you can recharge your energies... for a fee, of course.
- Day 13 [car]
Now, Třeboň, a really charming place! And excellent fish! After a visit of the city I moved on towards Telč, not before trying to locate a small countryside church in Hamr on the way and getting lost... because there are two Hamrs in the area!!! But this was serendipitous, because I got to meander through wonderful ponds and lakes and villages on some very narrow roads. So I cannot give a time estimate! :-D
*Comment: I think it's not Třeboň in itself the destination if you want to explore this TWHS, as much as it is the hub: there, you get to see the biggest pond (Svět, i.e. the World), which is nice, but to see the rest and to glimpse the actual network you have to dive in the surrounding region, away from the main roads. You have to plan accordingly timewise!
- Day 14 [car]
Visit to Telč, lunch and then onwards to Třebíč (0:40, maybe?). There, visit of ghetto and Jewish cemetery.
*Note: in Telč I unpleasantly discovered that the zámek (the castle/palace) was closed for very long restoration works. I wonder if it has already opened again! Better to check it. In Třebíč, to have a full architectural tour inside the houses you have to be a small group (2+?) and book beforehand. Else, you should manage to get the standard tour, which is still nice and insightful.
*Comment: it's worth staying here for a night. I can only recommend the pension in the ghetto: central and quiet place, you are inside the WHS to fully let it work its magic on you, and it's cheap with an incredible price/quality ratio. Just go at the information point in the Jewish quarter and ask.
- Day 15 [car]
Morning visit to Třebíč's basilica and then to Brno (also les than 1 hour drive) for the visit to Villa Tugendhat. Then I returned the car at the airport and settled in Brno.
*Note: as pointed by the others, you absolutely have to book your tour to the Villa with the largest possible advance. It can become really difficult to get one. I was extremely lucky: middle of July, planning the trip everything was booked and I was very sad; but I continued lurking and at the beginning of August one place for an English tour unexpectedly popped up. Less than one month of advance... thanks Corona! The tour is excellent and exhaustive. In my opinion, it does not make anysense to go to the Villa without one: you have to enter and to experience the space to see what's going on. You cannot understand from the outside.
- Day 16-17
Brno! I dedicated one full day to Spielberg/Špilberk, which has a legendary place in the story of Italy's independence. The exhibition Prison of nations (epic name) is ponderous, a little bit outdated in style, but rewarding. On the second day I admit running a little bit short of options, because I didn't want to visit art collections (still sated from Prague). But Brno is very alive, very active, I liked it a lot, and it has some other functionalist/modernist architectural perls to discover (like, yes, the crematorium on its outskirts).
- Day 18
Morning train to Prague and day of furious shopping. I managed to go up to Vyšehrad and closed the touristic full-circle at U Fleků (overrated, but irresistible).
- Day 19
Morning flight back to Italy.
* * *
It's probably evident, but this itinerary has a shortcoming: the juncture between Kutná Hora and the south is not well thought and not ideal, also for driving. The main reason for that (apart from planning last-minute like never before) is that the two cardinal fixed points were Kladruby and the Villa Tugendhat. Since the visit to the latter was the "most" fixed and unmovable and was set at the end of the vacation, I ended planning the whole tour around it, so a direction west-est and the need to do the not so ideal "change of setting" north-south.