The Pontcysyllte aqueduct is visually impressive and walking on top as well as underneath it is an amazing experience. Having said that, the surrounding area shouldn't be missed.

Getting there by public transport

As this site is quite big, there are several options.

If you just want to see the aqueduct: Get off at Ruabon train station and take the bus to Trevor.

If you want to do a decent hike: Get off at Chirk train station and start walking from there.

By boat

Several different canal boat trips can be made. Kayaks can be rented.

Hiking

Once outside Chirk train station, walk southwards to the Chirk aqueduct and viaduct, and the Chirk Tunnel. Go down and start walking northwards along the Canal. Be sure to use your phone light to light your path in this and upcoming tunnels. Some are quite long and could be claustrophobic. As not many people do it this way, some of the paths might be a bit overgrown, but rest assured it's a very peaceful part of the trail with amazing sights and other than a handful of other hikers and the occasional local you won't encounter many people. Once you get closer to the actual aqueduct, it gets crowded. Facilities at the aqueduct are limited and the site itself isn't that big either. Half an hour is probably more than enough to walk around, and observe, take pictures. One could take the bus from here (from Trevor) to Ruabon train station, but it's also possible to continue westwards to the beautiful old town Llangollen, a very touristy place. From there, I took the bus to Ruabon to get to Telford to see the Ironbridge.