Bo -
Really not sure on the CDL issue, if it is a motorhome with living quarters (sleeping, refer, stove, ect.) normally you would not need a CDL. If you where to use it as a businees, that maybe a different story.
With regards to maintanence, unless you plan to pound out a 100,000 miles a year, it will be nothing like what a trucking company experiences. Basically when these trucks hit this stage they are now retired meaning low milage under 50,000 per year and maintenance is not nearly a issue. I am sure others have a better idea on this.
Good luck and keep us posted
Bill
2003 28' Show Hauler Motorhome on a 1995 FL 120
www.showhauler.com