Your truck will be a very limiting factor. While I know there are truck campers made that claim to be half-ton (1500) friendly, you will very limited. A 1/2 ton truck just does not have the cargo capacity to carry the weight of a camper.
I am definitely not a 'weight-police' kind of guy, but I would be very mindful of the weight of the camper (camper/truck combo).
Good luck on your search.
06 Ford F-350 PSD CC FX4
05 Fleetwood Pioneer ASV 260FS
To get the most value for your current RV, you have to sell it yourself. That will take time, and there is no guarantee that you will find a buyer willing to pay more than what you might get for a trade in or direct sale to a dealer, if you can find one to take it.
A trade in is the easiest way, but the dealer will negotiate trade-in and new vehicle prices to get the best deal he can for himself, inflating trade-in and raising the sale price, or discounting sale price and lowering trade-in, depending on how he senses what will work to make the deal with you.
On a direct sale to a dealer, no trade-in, you will get no more than a realistic trade-in value. The dealer has no incentive to pay more, he needs to have room to sell it off wholesale, and without the margin on the sale of the new vehicle, a dealer may have no interest in buying your old one at any price.
Only you can put a value on the time it takes to sell your old vehicle yourself.
Sell outright for best buying power - you walk in with some cash in hand and one less thing to negotiate with a dealer. We sold two TTs on Craigslist over the years - use the NADA guides to help you price correctly, write a great description with as much info as you know, add good pictures. Good luck!
I've never sold a trailer but have sold cars/trucks on my own before. I always try to do that if possible because of the huge difference between what you get from the dealer vs. the person you're dealing with.
As for our trailer, we bought it used last fall on Craigslist. So far no problems with it. The guy was pretty stand-up and said if I needed any help getting it ready this year or questions don't hesitate to call.