I think if you interested in the 4115 you will be looking at a Dually.
I just did a quick look at the numbers which said the pin weight was around 3700lbs. The dry weight on that rig is somewhere between 16k and 17k. So, depending on what your hauling you could be pushing 20k or more loaded.
I have not had a rig that size but I have had a 36 foot Toy Hauler and you can pretty much exclude yourself from about 95% of National and State parks. And you will be looking for Big Rig friendly parks or open space.
I think If you go a little smaller on the rig you may be able to get a SRW truck your looking at... But I agree with whoever said you may be better off just going new when it comes to price compared to a 2 or 3 year old used Truck.
