It sounds like a lot of money for the RV, but the only way to be accurate is to compare the RV costs with the cost to travel to the exact same locations, by airplane, bus, train, or private vehicle, and then add in the cost of housing and meals for everyone.
RV's are expensive, but then again travel is expensive. Air travel has soared in cost and then there are the baggage fees, etc. I would be willing to bet that the actual cost difference between RV travel and alternative travel is not that great, especially if you have pets that accompany you during your travels.