First off, I am sorry to hear of your woes. I will share my humble opinion having owned many different pickup trucks, most of the heavy duty diesel variety, and a Lance 1030 camper. If you are truly interested in continuing to use the camper but are tired of expensive truck repairs, my recommendation would be to find a gently used 1995-1998 Dodge Ram dually 4x4 club cab with the Cummins turbo diesel. I happen to own one myself (I've had 4 Cummins powered Rams), and you will not find a more reliable, inexpensive performer out there because it simply does not exist. This vintage Ram came with a P7100 injection pump which never breaks down and provides for exceptional fuel mileage, and the detuned engine can be run at full throttle all day, every day and never get tired. What's more, they can cheaply be modified to safely provide easily double the factory power without sacrificing durability (though mileage will drop a bit). These particular trucks have been known to routinely provide over a million miles of service. The trade-off is they are short on creature comforts as compared to the newer trucks, but you can add an aftermarket NAV system, and improve some other aspects to your own tastes.
With patience, you will most certainly be able to find a one-owner truck in the 80,000-120,000 mile range from $14k-$18k. That may seem like a lot for a truck which is pushing 20 years, but when you compare it to the $65,000 sticker on a brand new dually diesel 4x4 from the big 3, it looks like a bargain, especially given the fact it will likely outlast all of them combined. There is literally nothing to the old truck. Just change the fuel filter at 15,000, the oil at 5,000-7,500, and drive it. You will have to replace tires and brakes, and change fluids, perhaps replace the odd u-joint or bearing, but you can just pile the miles on and never even think about something breaking. They are truly amazing, and yet so simple that any diesel shop can easily work on them. No expensive emissions systems to worry about, or high pressure fuel system issues.