http://www.classbforum.com/forums/f8/photogs-lifted-suspension-2009-roadtrek-190v-1552.html
Here is a good thread on guys doing a lift on Roadtrek campers.
If you are looking for a cheaper option on a lift, I have some info on what I did for my van (2017 3500 Express, 6.0).
Lift:
Front coil spring spacer for 1.25"-3" of lift can be sourced from these guys. They are the same as found on 1988-98 Chevy 1500/2500 2WD, 1999-2006 Chevy 1500/2500/3500 2WD trucks. A full list of applications is available on the site. They are the 1900 series lift spacers, and they work on Savana/Express models 1500/2500/3500 (1996-present). Talked to the owner Steve, who was helpful, and was able to figure out that these would work on our vans. Sent them out fast, I did the install, and he updated his site. Obviously not as trick as WeldTec, Boulder, or swapping in springs from a Duramax equipped Express, but a good way to start out.
http://www.mcbayperformance.com/Prod...e=1900T_SERIES
If you are doing a rear lift with just spacers, JEGS Performance was the best place to find what I was looking for. I only wanted to do a 1" lift in the rear. I utilized their universal lift/drop block, (which I did have to modify by drilling the guide pin hole to 11/16") and utilized a universal set of square u-bolts from Superlift Suspensions that measured 2.5"x10"x5/8" (Stock measurements for a 3500 Express is 2.5"x9"x5/8"). You could probably run a rear lift of 1-2" blocks with this assembly. Ran about $67 shipped for blocks and u-bolts, which was cheaper than I found for any kit. They have an assortment of sizes available.
http://www.jegs.com/i/JEGS-Performance-Products/555/60810/10002/-1
http://www.jegs.com/i/Superlift-Suspension-Systems/426/11004/10002/-1