You could always outdo Coore and Crenshaw out in the Heartland
! If you build a better-regarded course than Sand Hills, your client will certainly get his wish!
I really like the mountainous areas in northern New England. I'd love to see a better version of the Sugarloafs of the area. Maybe not the best scenery in the country, but darn close in peak foliage season, and it wouldn't be outrageously expensive, I'd think.
There's some absolutely gorgeous ocean property on the SC coast south of Pawleys Island, but north of Mt. Pleasant. There's very little going on in that stretch, but it's no further from Charleston than Kiawah. I'm not sure whether there are tough environmental laws on that area, but Mike Strantz designed Bulls Bay CC down there (Awendaw, which doesn't have much going on other than the Country Club), and I'm sure that you'd be able to give it a world-class neighbor. In the 120+ mile stretch (if you start at the boarder of SC and NC) down to Charleston, with so much golf, it's begging for a modern masterpiece (The Ocean Course notwithstanding).
Dare I say it, but the prices of big pieces of property might be pretty low (relatively) in the recently hurricane-harried areas along the Gulf Coast. I'm not totally sure, but it would seem to me that some people might want to leave those areas, making room for new development. Chances are quite low that such a devastating event will happen again anytime soon.
If you are able to, I for one would be interested to see where you and your client decide to build!
Best of luck.