New floors for my motorhome, laminate wood or tile ?

I don't know what your rig is and what weight limitations you may have but ceramic tile as a rule is pretty heavy.

You can use regular laminate flooring in potentially wet areas if you use a special waterproof glue they sell for that purpose and put a bead of silicon around the edge.
That is what I did in the step well and in front of the sink and refrigerator. We installed it several years ago and we have had no problems with it.