I hate to dig up an old thread but I've got something to add that some folks may find useful. My first question is did you
@mcarlo86 ever tow the Suburban behind the motorhome and how did it do?
One thing no one else mentioned is some RV's have frame extensions off the back of the frame to make them longer. Some of these are very stout frame extensions that may even be stronger than the factory frame, others I've see have been much smaller channel steel butt welded to the factory frame, and not suitable for towing at all. So a person really needs to look for that, you wouldn't want to tear off the rear of the RV going down the road.
Now my experience with towing with an RV. Keep in mind I live near the cascades so I know what it is like to pull hills and passes. At this point I've had basically two RV's note worthy here. Both of them I knew we'd tow with so it was high priority the frame extensions were strong. First one was a 22' 77 class C with the Dodge 360. Towed on a dolly our minivan I don't really know the total weight but I'd guess 5,500 to 6K. And we also towed my 1996 Jeep Grand Cherokee flat towed which is right around 4,200LBs. The difference between the two was very noticeable. We have also towed these two same setups with our current RV which has the 454, and is a 1999 so it's an injected vortec. The newer RV is bigger and heavier, than the 77, and it handles them both better, but in either combination the minivan slows ya down more. I'd say as long as you are 100% sure the frame is up to it, run a brake setup in the suburban and try it. The worst thing that will happen is you won't be happy with your ability to get up to speed and maintain it on hills and you'll never do it again.
Like you the idea of a Suzuki or any other sub compact car or suv is totally inappropriate for our life style. Frankly the Jeep is to small, but it's a compromise that works for weekend trips. For longer trips we'll still use tow the minivan once in a while.