Brad,
To get a County Card you have to be an actual member of a club in that country. For example, an English County Card don't apply in Wales and Welsh ones don't apply in England, so much for the 'United Kingdom' (but let's not go there!!!).
Jeff's Open Fairways sugggestion, where you buy into a scheme, is a good idea, indeed I've looked into buying into the scheme myself, and there are good savings to be had, but don't get you hopes up to much as the scheme is limited to certain clubs/courses and lots of the ones you'd like to play arn't on the list. For example in South Wales, Royal Porthcawl, P&K and Southerndown are not within the scheme. Of the courses you mention, Pennard and Ashburnham are, as is Tenby. Some clubs also have a accommodation at the club Tenby, Ashburnham, RP, Clyne, Newport-Pembs, maybe P&K(?) and give cheaper golf if you stay on-site so these may be worth looking at if you're thinking of heading westwards.
There is a full listing of all the courses on the scheme on the Open Fairways website -
http://www.openfairways.com/opencontent/?itemId=1Also, worth considering if you can show a valid handicap certificate (if requested) are Open Competitions at various clubs, including the top level clubs. These are usually reasonably cheap to enter and there is a website called Golf Empire -
http://www.golfempire.co.uk/ - which lists them by region/club etc. You can also research them by looking at individual club websites. Some open comps can be entered on-line, some via post. If you're interested in one and wanting to enter from overseas I suggest you contact the clubs secretary by email and take it from there.
atb