2500 Rust removal/restoration

So my 2003 2500 looks pretty good for a 13 year old truck but years in NY winter salt (previous owner location, obviously didn't take care of the truck) and now MI has put a toll on it. The rear bumper frame is rusted out, I've already put $2600 into rust repair after finding rust under cladding. The frame has a lot of rust build up on it and I have found the front fender is rusting out as well as the lower rear door jam of rear passenger side door (had the left side repaired already). My question is, is it worth dumping more money into this thing? Is it a rare enough vehicle to restore and hold on to? Should I consider a frame off restoration since the frame is so rusty? I love the truck, it hauls the family and our 33ft TT with grace and it looks awesome (as long as you don't kick the rear bumper or look under the truck  ). Should I just leave it as is and let it go? I am planning a new truck purchase within the next few years but would maybe like to turn this beast into an off road vehicle of sorts (lift, tires, etc). Just not sure it's worth putting money into. What do you think??

It totally depends on how much you love it, a frame off resto job will cost you plenty of hundos. As far as the frame it plenty accessible to restore from the underside of the truck. Now the body is a different story no one makes patch panels for the rear so either find a AV with good ones in a junkyard or have them custom made.

Eastwood makes some pretty good frame resto products. I also have started having rust under the cladding problems. 

https://www.autobodyspecialt.com/cgi-bin/commerce.cgi?preadd=action&key=C-860C-RH

Yep LOL, they even make panels for the lower ones behind the cladding

If you are going to go with a cleaning/restoration, do it frame off. I did a cleaning with my 02 back in 08-09 I left the body on, and it ended up doing a pretty good job, however now 7 yrs later, it needs to be done again. I wish I had separated the two back in 08 and powdercoated the frame after doing the rust removal.