My recipe is simple.

Toss varmint carcass in roasting pan/slow cooker/crock pot.
Chop up some carrots/potatoes/onions/celery/garlic/etc. and toss in with varmint carcass.
Season it like you would roast beef or meatloaf.
~350° until the bones pull free with little to no resistance.
Serve it up.

If you like it with BBQ flavor, pull it out of the roaster before it starts to fall apart, transfer to a hot charcoal grille, and finish it there.
I like a sticky sweet sauce on varmint. Bone Suckin' Sauce and ShowMe are probably my favorites.

I've heard of people doing the boiling thing, but I've never understood the purpose for doing it.
To my way of thinking meat and water only go together if you're making soup.