A little more elaborate frontier fort would be Fort Stanwix. The US National Park Service has reconstructed it. Their website is very good. http://www.nps.gov/fost/ There was extensive fighting there during the Revolution. It is really a wooded version of a Vauban fortress.
Another extreme example is Fort Klock. It was really just a fortified farm house that same some fighting in NY State in the Revolution. Their website is http://www.fortklock.com/intro.htm
The actions at both sites are well within reasonable range to war game. And both sites are well worth the visit if you are in the Mohawk Valley of New York State.
If anyone is in the Washington area before March, the Smithsonian currently has the exhibition "Clash of Empires: The British, French & Indian War, 1754-1763." It's been making the rounds in canda and elsewhere in the US.
It's a nice overview of the north american war from all sides. They include a fabulous diorama of Fort Duquesne (i'm guessing about 6-10mm scale.) and another one of Braddock's defeat. same scale.
Zvezda are really rather good with their modular fort designs. Better buy the wooden fort rather than separate bits - cheaper.
As for any internal buildings made of stone, you may have to visit a model railroad shop for scratch-building materials such as stone walling etc and go from there.
good suggestions from you all. i'm really looking forward to this project. as it is, i'm painting a lot of ARW figures that i put on backburner because of napoleonics. the imex artillery sets and italieri indians made me interested in the period again as a possible wargame. thanks again for the info people, and happy new year as well. (i'm off the forum for seven days.)