Wales in 4 days
 

My husband and I have rented a car for a 4 day trip in Wales this September at the end of a business trip/stay in London. We are really interested in seeing castles. Any suggestions of a route or any 'can't miss' places to include?

Don't miss Carnaervon Castle, which is near the town of Llanfairpwllgwyngyllgogerychwyrndrobwllllantysilio gogogoch.

I loved the little train in Llanberis. it's a beautiful ride to the top - hike down.

Canaervon (sp?), Conwy, Harlech, Cricceth and Beaumaris.

Chepstow,Cardiff, Caerphilly, Castle Coch all within the Cardiff area, Caerphilly being the largest in Europe.
or visit:
http://www.greatcastlesofwales.co.uk/map.htm

Muck

I agree with Mucky. You can visit all the castles listed plus the city of Cardiff itself. Nearby is the Museum of Welsh life at St Fagans as well as Cardiff Bay with it's wonderful waterfront.
Only an hour's drive away is Carreg Cennen castle - surely the most dramatically situated castle in the UK? If you need to locate it on a map, it is near the market town of Llandeilo.
South Wales also has a dramatic coatline, including around Bridgend and the Gower.

One thing I forgot to say is that with only 4 days, you'll have to choose either North or South Wales as to do both would be fairly impossible.

AR Quite rightly mentions Carreg Cennen castle , have a look at the film in this site.

http://www.worldwidewales.tv/index2.php?mid=131

Muck

In addition to those you already have, Pembroke castle is quite a gem and, if you are interested in the history as well as the views of castles, you might look at the old Welsh castles at Dolbadarn, Llanberis and Dolwyddelan between Bettys y Coed and Ffestniog. [Most if not all of the others were English castles built to subdue the Welsh.

Other posters have covered castles pretty thoroughly. Also try and see the Italianate village of Portmerion on the North Wales coast, location for that wonderful cult TV series "The Prisoner".
St Davids on the South Wales coast is a spiritual centre with atmosphere. Interested in literature? Dylan Thomas's boathouse oin Laughanne is worth a look. Books? Hay-on-Wye will blow you away. While driving in Wales, tune into Welsh radio - you won't understand a word of it, but the pathos and music really tugs at the emotions.