Yeah, it's possible to get them out without unhooking a lot of stuff, I don't know about A/C equipped Rangers though... The trick is to sort of slide them under the wiring. The old wiring can get fragile so becareful.
You might also strip out the bolt holes from over tightening. I always lightly snug them up, get the engine warm and torque them down to spec. (Although I do not have those numbers handy) Check them for straitness on the edges while they're out. I am also thinking there is a sequence to follow as well.
I've used cork or rubber w/ no RTV (on several different engines), but under new valve covers. A lot of people suggest it, there's no reason you can't, it's more difficult to get them on and sometimes can be a mess to clean up later. I would more than likely if I had a buggered up valve cover to close up the gaps.
Pete