I've used Single-Sixes, Mk. I and II autoloaders, Contenders and FA revolvers since I began squirrel hunting with handguns in 1961.
I'm guessing you might live in Pa. where autoloaders aren't legal. They're legal in N.C., where I live, but the .17's aren't. I'm told, though, that the .17's do a great job on tree squirrels.
The .45/410 T/C handguns aren't legal for hunting squirrels here, either, but I've used one in other states, and they're a hoot.
Your choice of either a Contender or Single Six Hunter will fill your need well, and either can be readily scoped when that day comes... and it almost certainly will.