The Wye Valley Walk, Monmouthshire
A 136 mile walking trail that follows the course of the River Wye from Chepstow to Plynlimon near Aberystwyth. It mostly takes you along the river bank, with a few diversions through meadows and rugged uplands, so it's actually a very good mix of hill and river walking. Just stroll along part of it, it doesn’t have to be an all out ramble, make it as long or as short as you like. Find a riverside pub and have a relaxing pint, or take a picnic; the scenery is spectacular and the wildlife is abundant so be sure to take your camera.