I think based on the fact you have a tool box... You should be fine to evaluate the "chassis" part of the equation..
Basically, if you're competent enough to buy a car, you shouldn't have too much of an issue purchasing an RV with a gas chassis.. if it were diesel.. well, that's a whole 'nother set of rules..
As for the "coach" portion... The number one question I would ask; when was the last time the RV was used on an extended camping trip? I think this is a pretty valuable piece of information..
- If the answer is a year or longer.. well, you better bring out your Sherlock Holmes magnifying glass and go over that rig with a fine tooth comb... Having any system sit for extended periods of time is not good.. without having a good working knowledge of RV systems, you may want to get a professional involved
- If the answer is less than 6 months.. I would think having the current owner go thru each system and actually demonstrate it working could be good enough..
- Running the generator with load (AC units) - let run for more than 5 minutes if possible
- Running everything electric - both via shore power and generator
- Running water thru the system (Both city connection and holding tank operations)
- Turn on and run the stove burners/microwave/convection oven/oven
- Toilet operations - flushing clean water is fine - let him "dump" all that clean water in his lawn to show you there are no issues in the wet bay
- Running the furnace
- Go onto the roof and check all seams and caulking.. look for any damage
Basically... run everything the RV has to offer both on generator and shore power.. run water to every faucet and/or shower.. and if you're a complete newbie.. video tape the current owner doing it so you have a reference on how to do something.. spend specific time on the wet bay.. how to run water from the city, how to run water from the holding tank.. While doing this portion... try to be on clean dry pavement so you can see if any water is leaking underneath the RV while testing all water systems..
Obviously on the chassis part.. ask for records.. belt changes, filter changes, tune up's... anything you'd ask if you were buying a new car.. and don't fall for the "mileage" answer.. all the above need to be changed based on mileage AND/OR time... usually its "time" with RV's..
---> find date codes of the tires (even check the inner duals of the rear)... If they are past 5 years, you may be able to use that as a bargaining tool.. they will need to be replaced soon and that is no cheap date... and it doesn't matter how good they look.. or how few miles are on them.. the UV rays ruin RV tires, not mileage..
Finally... I didn't notice your location.. maybe if you let people know where you're at, someone from IRV2 will spend a couple hours free of charge.. I know I would if you lived in my area (Milwaukee, WI)..
Finally.. keep in mind.. you are buying a 20yr old house and car.. no matter how well you inspect it.. things will go wrong.. it's inevitable.. especially when you start driving it and it bounces down the road... don't be discouraged.. just make sure you have a "warranty fund" you can dip into should the need arise..
Good luck !!!