First Thing: Weigh your truck.
Second Thing: Do the math.
Third Thing: Beware the local RV dealer.
I have a Ford F150 with next to zero payload as well. Last week I happened to stop by a local camper dealer and asked the salesmen what he had that would work with a 1/2 ton. He walked me past two small campers designed for Rangers/Tacomas/Dakotas and showed me two hard side campers with bathrooms and sticker weights of 1800-1900 pounds.
I've been around long enough to know that a 1800 pound camper will probably weigh 2100 or 2200 pounds empty before I fill it with another 400 or 500 pounds of stuff.
I wasn't seriously looking and didn't say squat when the salesman walked past the two campers that wouldn't crush my truck.
Realistically, you will need to stick with a 6 to 7 foot pop-up or a very very small, bare bones, hard side. A simple clue is, if it has a bathroom, it's too heavy.
