Probably the same places I would potentially do well in - high income, moderate, and not very religious, who won't totally freak at a GOP label. The trick is to win both the primary and the general election, and those twin goals can be heavily at odds with one another. Pity there are so few of those places, but the north shore suburbs of Chicago, some of Montgomery County, PA leavened with a few extra GOP precincts nearby, the northern parts of San Diego, maybe Santa Barbara County plus San Luis Obispo County, maybe certain carefully selected parts of Orange County, maybe far northern Westchester County plus Putnam County, come to mind. As a Republican, the available congenial places are rather thin on the ground these days. New Hampshire has a zillion assembly seats, so sure, we could get elected in some of them, and be one of 400 members or some insane number. Something around Seattle might have potential, taking in Mercer Island and Bellevue, and the posh areas of Seattle itself (eg Washington Park and Madison).
haha all of these things apply to you too.