Do the math of what it would cost to buy an RV, fuel, insurance, registration, and CG fee's BEFORE you take that plunge.
Although it sounds real nice to take your children camping in the RV when you have them, you will find that renting an apartment to be way less expensive leaving you more money to do more with your children.
Sitting in an RV every weekend gets old real quick for the kids. IMHO save your money and take them out in your car to different places.
Just saying, do the math $'first'$! :C