With older campers, if in good condition and light use (a real possibility with a camper, not so much with an older pickup truck), the required repairs for long life will be mostly "tinkering". Some caulk here, fix some screws there, replace a faucet or pump, etc. Easy stuff mostly save for replacing a fridge or slide out assembly. AND very few things go wrong w a camper that render it inoperable. And even if it was, you still have a TRUCK.
By comparison, there are MANY things can render a truck inoperable, simple or not, that can't be remedied in the woods with some gorilla glue and a couple stainless steel screws, lol.
Thinking from worst case scenario working backwards, it makes sense to buy a top notch tow rig and a less expensive camper.