We purchased our first RV last year and had an additional bonus! Nearly every problem listed by every report ever written happened. An RV is the second most expensive purchase you are likely to make. Here is what we found:

• Water damage. the number one RV killer! The manufactor puts more cuts and seams in the roof and sides of the RV than ANY OTHER vehicle! Here is what you do..,
• Take a water hose at the dealership or private seller and soak the camper! Yes, they are going to think your strange, but right now, finding water leaks is FREE for you. Not so later on. Around the awning, slide-outs, windows, windshield, doors, vents, air conditioning unit(s), spot lights, antennas, ladder and luggage racks, basement storage. Hold the water on the item for 15 -20 seconds with another person inside by the area in question looking for signs of leaking. Better yet, take it to a Truck Stop wash and pay to have it washed, then from the inside, watch what happens. You are looking for streaks, like when makeup runs on a person's face, where the roof meets the wall, inside cabinets, on shelves, under bed/seat storage, under windows, everywhere! Wallpaper should never bubble! Feel the wall with your flat hand in these areas, it should be as smooth as the dashboard. If it rolls or bunches up, it probably has water damage. Does the wood look like it is peeling? Water damage!
• Have the seller start, explain and operate EVERY appliance!
• Furnace, cabin A/C, coach A/C on the dashboard, microwave, refridgerator, stove top AND oven, fan, light, inverter, cabin/coach batteries, leveling jacks, water heater, it will light and heat, if no water, make them get some!, because you want to fill the fresh water tanks to check for plumbing leaks, every sink, basin, washer/dryer, shower, toilet, follow the lines, do they leak at fittings? On board water pump, and have them explain and operate the septic tanks. Operate the slides, does it hesitate and slip? Then it is GOING TO FAIL, on your dime! The first appliance that fails will cost ONE MILLION DOLLARS to repair/replace. Ours did. Where will it fail? In the middle of the desert. No help. I had to replace the leaky toilet flush valve, among other things. I am 6'2, 280 lbs and the bathroom is very small! Our refridgerator failed, as did the onboard water pump, overhead lights, brakes, and tires.  
• Inspect the RV for a road test.
• The tires for tread depth, small cracks near the rim, this a dangerous condition known as weather checking, this is more important than tread depth!. Are the tires properly inflated, especially the inside dual tire? Air suspension system inflation, operating lights, horn(s), bumpers, basement storage locks, spare tire. Are all the windows closed and secured? We had a window come open while driving and it slid off the track and almost fell out! Hub caps tight against the rim? How much damage would a rolling hubcap do on a busy highway at 70 MPH? Check the oil. Black oil is old and dirty, time to change it. White foam and bubbles in the oil is a serious engine problem, a gas smell in the oil is a sign the engine is having trouble starting and/or running. Transmission oil should be pink and no burnt smell! BRAKE FLUID! Check it here with your hands and eyes or at 35 MPH with that motorcyclist in front of you at a stop light! 
• Test drive. Yep, its huge, but it should function like your vehicle. 
• Figure on a 20-30 minute test drive in as many traffic and road surface conditions as you can. 0-65mph on the test drive, cornering, braking, shifting. Does the steering wheel pull in your hand on different road conditions? This will be a noticeable pulling to the center or edge of the road. This is an alignment issue and will need to be fixed. Does the motor struggle, does it seem to be racing? Does the transmission shift the same way cold, warm, and hot? The first shift should be identical to the last. The test drive will tell you how the vehicle was driven and maintained. Does the motorhome come to a complete stop with no pulling when the brakes are fully operated? Any swaying or pulling while braking, hard or easy, in any condition, is a sign the brakes have been compromised and are operating at a decline, they will give out without repair!           
• What the seller claims not to know, YOU WILL FIND OUT!, Don't let them plead the 5th ammendment. Buyer Beware. When you are in the market to purchase an RV, it is a BUYER's MARKET. This is not an impulse purchase, no one is seriously considering this RV, there will not be anyone coming this afternoon with the money to take away this RV. Do not fall for these sales tactics. If they do, you are on ebay! You will find another one with the click of a mouse. 
• Yes you can afford to purchase this RV, but carefully consider the cost of repair. RV's mileage will rarely match the same as other vehicles, because they normally are not as travelled in as other vehicles. Expect driveability issues earlier than you might think. 60,000 to 70,000 miles is a TON of miles on this type of vehicle. Think of it as double the face value. 52,000 miles to an RV is the same as 104,000 on a daily driven vehicle, and so on.

With these tips, you will be successful in your puchase and operation of your new or new to you RV. Enjoy!