Probably doable,as long as your max overload is 200 lbs over your GVCWR.
One thing to keep in mind; liabilities issues are possible. The insurance company and truck warranty's could void coverage and any submitted claims refused.
Another item that might be considered, some state DOTs are pulling in RVs and checking their weight to see if any are over gross registered weight, or the manufactures wt ratings posted on the door jamb,but if your only over 200 pounds then your ticket for being over gross will be only $200.00.
either way I would say be extra careful.
Might want to think smaller RV, or bigger truck; to give yourself an extra bit of cushion to play with.