We routinely tow a 5K lbs modified Jeep Wrangler Unlimited behind our 23' (25' overall length) E450 class C with no problems. I notice a significant decrease in available power adding the Jeep behind the motorhome, but with our supplemental brakes I notice no difference in stopping. We seem to be able to pass all the big trucks (barely) on the big mountain passes of Colorado, and consistently get 6.5 MPG.
If you're not a patient person, a heavy toad might aggravate you out west. We don't mind as having the Jeep available for our destination 4x4 adventures is... priceless!