Last December, my wife & I traded a 2000 Winnie Chieftain with the Ford V-10 and Banks Power Pack for an '08 Simba FRED, model 38 SDS with the 300 hp Cummins and 5 speed Allison tranny. We've had almost all types of of RVs but never a diesel. Contrary to what's posted elsewhere, the FRED is much quieter than the Ford, has more power, is smoother, and in the mountains, leaves the V-10 behind.
Ours had 12,000 miles on it, supposedly from a Council Bluffs, IA dealer who rented it, as the owner's manuals were clean and without grease thumbprints! We've since put 8,000 on it from Tucson to Sioux Saint Marie locks and it's very trustworthy. Because we were the first owners, Freightliner gave us a $1500 Visa card for fuel, which is long gone!
This model has a hydraulic lift instead of a ramp and its load capacity of 3300# is fine for our Gold Wing trike but the length of the lift platform has no room to spare. We've used 4x4 blocks to prevent rolling off the back during the lifting, but will change to a come-along strap in the future.
The Simba has 4 floor plans but ours has a single slide and with a narrow hallway and 3 doors that are often in each other's way.
Pulling the Wrangler and carrying the trike, we get almost 10 mpg when on cruise at 55 - 60 mph.
You probably know that the brakes are hydraulic, not air, and the suspension is not air.
We chose this over a very large Class C with hydraulic lift because of the high window square footage. We also have dogs and the tile floor is a breeze to keep clean.
Good luck and enjoy RVing.