James
If Minch Old etc are too far off the M4 you can try Players Club Stranahan course or Cumberwell Park Orange 9. Both are new courses with interesting designs that shouldn't be over-taxing for the 1st day of golf just off the plane.
Southerndown is a must play near Porthcawl. Tenby is the next best in the general area...its about 1.5 hours west of Pennard. Clyne is easy to play as its less than 10 minutes from Pennard. P&K and Ashburnham are not special and should be reserved as back up courses.
Should our diaries match, I am happy to give you a game at Burnham. The club is 30 minutes from the M4/M5 junction.
If you want to stay in a quiet spot, close to a beach, a few simple "restaurants" and a pub...try
http://www.culverhousehotel.co.uk/Swansea isn't a great city, but if ya have to have it...dead centre there is Morgans and Premier Inn...both have parking. There are also big hotels in the Martime Quarter...not too far a walk from the centre. The Mumbles is just down the road from Swansea...though I am not a fan of the place and places to stay are sparse.
I tend to think of heading off to Huntercombe, Painswick etc as a separate trip given only 6-7 days and as much as 3-4 days devoted to Pennard and Porthcawl. It makes more sense to focus on the courses directly enroute or near the must sees.
My suggestion would be something like
1: Burnham or Stranahan or Orange 9
2: Porthcawl
3. Pennard
4: Pennard
5: S'down
6: Burnham (if couldn't do day 1) or one of many heathland courses near Heathrow...Woking would be my suggestion
7: If time allows another heathland course...if not...fly
Ciao