You have received so much spot on advice thus far. Here is my two cents. My perspective is that of a brand new RV'er who has a 6 year old, has recently driven from NYC to LA and just purchased a used and former rental 25 ft RV.
Here are my new to the RV thing observations or things I have noticed that I didn't consider before purchasing. They may help you a little. One, driving 5 hours in an RV feels like 10 hours in my Mini Cooper. It takes more concentration. Two, driving in an RV takes almost twice as long. Literally. Three, the learning curve is higher than I thought and the appliances don't really work like normal house appliances. That goes for the toilet, fridge, stove and more. I assumed I was basically buying a house on wheels. Not so much. It is a "special" house on wheels. LOL. We mostly dry camp in our RV so that presents even more special considerations. Four, it is not safe or practical to let your kids run around in a class C RV like it is a house. For some reason my brain pictured this possibility but this is not a reality in a class C. This makes long driving trips almost as tedious for kids. Five, some people and kids and dogs get sick in a moving RV. These things bounce and shake like a boat. Six, if the brochure says it will comfortably sleep six then count on maybe four small people tops. Seven, after you buy one you still have to spend about 1k or more getting it ready to use. Sheets, pillows, pots, pans, chemicals, hoses, and more. It adds up quickly. So for all of these reasons and more, I would suggest renting one for a long weekend and trying it out before going out for 40 days. You may love RVing. We sure do! :)
One suggestion. If you are stuck on buying instead of renting and If your budget is tight take a look at buying a used RV from Cruise America. Their RV's have more miles and are generally older but they are cheaper. I just did. Previously, I spent a few years looking at private sales that were roached out and needed 5k in work and were still selling for 30k plus. I got one for under 20k with new tires, brakes, tranny, new bedding, belts, new paint, new battery, all appliances only a few years old, and they let me stay there for 8 hours with the guy who fixes the RV's while I made a list of 42 things I wanted replaced or addressed and they replaced them on the spot, no questions asked. Try that with a private seller! They even let me come back after two months and fixed a few more things I missed or wasn't happy with for free. They refurbish them with new paint and other items as well before selling them. IMHO, any first time RV buyer who will not be keeping his RV for a long time (I will likely sell or trade mine in in 4-5 yrs) and is just a weekend warrior like me should strongly consider this option. I now own a nice and fully functional weekend RV for what I would have paid for just the down payment on a new one in the same class plus a 10 year mortgage for an additional 40k. Yikes!
That said, it is not a good option for everyone. The negatives include a very basic RV with no frills, an engine you will likely be putting at least a little money into each year after the warranty is up unless you get the two offered extended warranties for five years assuming they cover the potential issue, a slightly used look, a slightly under powered engine in the mountains IMHO, and more I am sure I will discover as I learn more and use it more. Of course you may still end up with some of these negatives buying from a private seller used or even buying new.
Random answers: Slide outs? Not worth it but this is coming from a former and avid tent camper. I agree with getting a shorter RV. Many of the best places have size restrictions or a lack of spaces for RV's above 24 feet especially in the west and here in California. Plus, I can still easily park in most lots. One AC is fine. Spend more time in the west. The state and national parks out west are AMAZING! My wife still hasn't driven the RV. It scares her and to be honest it scares me a little too but then again my daily driver is a mini cooper. :). In California, buying a used RV froma private seller isn't easy. There appears to be two types of people here in Cali. One is the RV owner and the other is the person who wants to buy an RV. Californians love to camp and that reality drives up prices and dries up inventory. Maybe better in Florida? My daughter loves the RV. It has brought us closer as a family. No tv, no internet, just long hikes and plenty of card games!
I hope my ramblimg helps. Good luck!
