No one has mentioned the Wye Valley, absolutely gorgeous now, lush green valley with lovely areas to stop along. Buses run the length.

You could do, Chepstow (with a big Castle and Normon Church, lovely town lots of pubs and museum), then Tintern, (big Cistercian Abbey and lots of pubs, and walks in that area great views) down to Llandogo for more pubs and nice scenery, then Monmouth - busy market town, lots more pubs (my band play there in a pub once a month). That also has a museum, then there's Hereford - with the big cathedral and the Mappa Mundi in it. Erm, definately a trip to Hay on Wye is worth it, especially if you like books, then on to North Wales from there.

There you go...

Hope that helps (though Newport Museum is pretty good - it is a bit of a grey old town, although I spent 4 excellent years at art college there, the craic was good, just a bit industrial - just so you know what to expect)

Regards

Have fun

Ella