Meguires is an excellent wax and all I would ever use on my '57 Ford. But for a 14 year old dull MH, the Red Max (now Zep) process is the only thing left to give showroom results. Mine is on now for 3 years and I've had to redo the front cap twice (I;m pretty agressive on the bugs) and the entry door once (poor preparation on first attempt).
Suggest you do a search for Red Max Pro on this forum and decide. The only people who poo poo it is the people who haven't tried it.
I would not use it on a full bodied RV. Common sense should prevail.