Looking to do a sink/counter remodel on our 1998 Jayco Eagle 12 UD......lots of cracks and warping.....any thoughts on the best material(s), processes, best practices, etc? thanks in advance!
Welcome. Good places to begin reading are "In the Garage" and "At the Campsite". For instance, "In the garage" has sections on restoration, mods, and other parts of the camper. You'll find all sorts of ideas, and if you need to ask a question, finding the area that is closest to what you're working on and using a good subject heading usually gets the best responses.
For what it's worth, the first counter replacement we did in our first popup (1984 Palomino) was done with too-thin plywood (maybe 3/8") and laminate, which soon warped. We ended up buying a pre-made countertop and using that. We did not have a sink.
I replaced the counter in my popup a few years ago. I went to a building materials recycling center like the Habitat for Humanity store and found a formica bathroom counter that was bigger than I needed and cut it to size. I first made a template using plywood and laid out the sink and the faucet and tested everything in the trailer and when I was happy with it, I then used that template to mark the final countertop for cutting. I taped the top with blue painters tape before cutting to reduce the risk of chipping and used a fine blade on my circular saw to make the cuts and it came out pretty nice.