i think it is a great idea!
(as a background i may add that i learned finish carpentry/ fine woodwork for 4 years in switzerland and worked over 15 years "on the road" remodeling high end Hotels, Bars, Nightclubs and Restaurants)
IMHO the quality of many RV interiours is just downright horrible
; there should be lots of work out there for you
if you have a love for details (and customers that appreciate your work) word will go around quick
i say go for it