If a choice is had, it is always better to be lucky than talented. You have just been unlucky. I have pondered (Ponder, RIP) what to do if faced with a lemon. We have had lemons and tried both ways to make it work:
1. drop kick the sucker, take your losses and move on. Life is too short to second guess that decision.
2. keep spoon feeding the woes with temporary fixes, which don't seem temporary at the time.
It is still a crapshoot when deciding what to do because the end is never in sight.
We have made #1 and #2 work for us. It's the decision on which way to go that becomes the problem.
What you want is the lowest amount of cash-echtomy. But there is a hidden charge which is the aggravation and depression that comes with constantly dealing with a lemon, hoping against hope that this is the last hill to climb. The general rule of thumb is that it is cheapest in the long run to keep fixing up the old crate and hope for a change in the weather. Where the triphammer swings the other way is your call.
Since you are still relatively young; your pain threshold is high; it might work to cut your losses and buy a scaled-down size camper loaded onto a used gasser. This way you are not paying the diesel surcharge but using tried-and-true V-8 or V-10 tech.
We bought a VW Dasher diesel wagon new in 1981. At first it was great, if underpowered. By the time it had 32K miles it was done....as far a Jeanie and I were concerned. You could not keep a starter in the thing. The entire electrical system went berzerk, among other things. It was off warranty and could not be driven. We had it towed to the dealer we bought it from and just left it on their doorstep with the keys in it and walked away. We lost big time on that one. In retrospect, I can see the aggravation release was the most important thing.
Our next car was an '83 Peugeot 505-S turbo diesel, 5 speed sedan. Whoda thunk that would go 200K miles and have so few woes? And be so comfortable and fuel efficient? Besides our Cummins, still the best car we have ever owned. Although, Jeanie's 2011 Grand Cherokee is creeping up on the Peugeot record.
jefe