Found this thread while looking for wheels options for a 22 DRW. As a retired tire guy I wanted to to add my .02
2" "Adapters" will move your outer wheel 2", all you need to do is put a tape measure on the sidewall bulge and see how far out of the wheel well 2" will be. Adapters are ok provided you re-tourque the inner lug nuts every 100 miles or so until they maintain trq.
Spacers that slip on are extremely dangerous and should never be used on anything, much less a DWR used to tow. They very rarely maintain proper lug nut torque. I have seen them break on Tuner cars and lightweight jeeps. There is a reason no reputable tire chain will install them. Our tire shops won't even work on a vehicle with slip on spacers, way too much liability. Have people run them and never had a problem in 20yrs, of course they have & still do, but Grandpa only died once. Use what you are comfortable with
Lugnuts should never have exposed threads (from studs being too short). There is a very good reason they are as thick as they are, and they are designed to have full thread engagement.
Wider tires on stock rims. Yes you can, but realize that the tire manufacturers have a minimum wheel width for a reason. They can and will deny warranty on a 255 mounted on a 6" rim as it is too narrow for what the load carrying capacity was tested at. (its how they cover their ass in liability) The more you pinch in the beads (from 6.5 to 6 wide rim) the less carrying capacity of the tire, especially at lower psi.
I have run the 255/17 Toyo AT3 on the stock wheels without spacers, with 70psi fr & 55 psi rear. My DWR is our tow pig, of the 80K that was on the 2018 50k of it was towing a 22k lb 5th wheel with a tongue weight of 4200lb, my rear tires never touched and wore flat, but do what you are comfortable with. The thing I didn't like about the 255 on the stock wheels was the edge wear of the front tires. I rotated the tires twice while they were on due to edge wear on the fronts. I believe the edge wear is from the tire being on a wheel that is "technically" to narrow for it. You could just replace the fronts when the wear got too excessive but I opted to put the stock size back when the 255 were done. I think I got almost 40k out of the 255s, but I replace tires earlier than some due to the weight, speeds, weather & milage I tow.
Now I just have to decide if I am going with 6.5 wheels or stepping up to the 20" rims and paying the $1k for a set of tires. Decisions decisions