Saturday, 3. November 2018 Luang Prabang Phovasan Bus
Going to Plain of Jars (8h tenuous bus ride). Hopefully scenic.
Very scenic! I did it too in 2011. 13hr bus ride from Vientiane to Phonsavan, and then 8hr minibus to continue to Luang Prabang. Expect delays.
Monday, 5. November 2018 Phonvasan Pakse Flug 13:20-18:45
This may seem insane, but Laos Air offers a flight from Phovansan to Siem Reap via Pakse at the cheapest prices.
Vat Phou takes about 1.5hr to see. Travel time there from Pakse by car should be less than an hour. But beware that most things are slow in Laos. It's not nearly as efficient as Vietnam or China.