goufgators, AstroRig57 gave you supurb info as did some of the others, here is an add on just incase. Winnebago keeps a file of the key codes for all their vehicles, to find out the code or order a new set, contact W.I.
I went to the local keyshop, not more than 10' X 20', they had the Ilco blanks for our Trimark locks. The door key blank is KS101 and the deadbolt blank is KS201. There was a $1.00 surcharge for the spares. So for the ten keys I bought, it cost me $20. Now there is a set in everyone of our vehicles and one in the key locker in the garage. The original keys also had the cut code but were so worn that they wouldn't work in every lock.
A hint, I am notorious for losing or misplacing keys so I have a full set of keys for the RV and the Towed in a hidden place in the rig. I took a entry and cabinet key and drilled a hole in a piece of sheet metal under the hood, using a screw and wingnut, I mounted the key out of site but in an accessable spot. Now we can get in and all of us know the location of the spare keys. We have the RV, two toweds, a DD, and the various towing locks, so the number of keys is pretty high.