A body parts availability

Help the ignorant here, please! I'm looking to pick up a new toy next spring (it's been eight years for me!). Now, I'm not skilled as many of you are in keeping old rides going. And it takes no crystal ball to reckon Mopar collector cars--no matter whether they're A, B, C, E or FMJ bodies--are not as easy to find parts for as collector Mustangs, Camaros, Corvairs, Bel Airs or even Studebakers. But are there any Mopar collectibles (I even go as far as K and P body cars!) that aren't a bear to find parts for? I've looked through Rock Auto's site, comparing the availability of given parts, but that's not yielding any clear signs for me. All opinions appreciated!