Purchasing a low mileage, low use gas MH

Look for stains on the inside ceiling since caulking and sealant could have dried out and leaked. If there are none, great but plan on going over the entire roof to reseal all joints anyway.
Check the water pump since I assume they only used shore water rather than filling their water tank. Change water filter if there is one under the kitchen sink.
Tires are probably gone from age(2006 date?) and sitting in one position.
Check for any rodent damage and insect infestation.
Generator probably needs at least a carb rebuild due to not being prepped with Sta-Bill or other gas conditioning.
Check to see if the coach was Winterized since water would still be in the water lines if hooked to shore water. Check water heater and all other appliances for electric and LP operation.
CO and LP detectors are probably out of date.
You may consider new engine belts just to be safe and obviously check all hoses for deterioration.
Snug up roof top AC bolts.

everything the first post listed , tires are in the $300. range EACH. double check for wet spots if you find ONE??? RUN.

Seven years is a long time for rubber to go unused. I'd be concerned about belts/hoses etc being dried out in addition to the tires.

Look at changing all filters and belts, tires including spare, service the transmission, fuel pump could be weak and fail shortly due to non-treated fuel. Fuel lines to generator and it's fuel pump could be bad if it sat with untreated 10% ethanol fuel. These are all things we had to address on our 2004 R-Vision B+ that had sat for 4 years, when we purchased it in 2002 with 8,000 miles. Also check the refrigerator for any recalls and if they were performed.

Sounds like you have found a jewel! If stored outside in a hot arid climate, check all of the roof caulking to make sure it isn't dried out and cracking. Tires and rubber parts may be needing replacement.

Is the registration and license up to date? In this state, if unpaid, it get turns into big $$$.

Replace all the break fluid and lube the brake caliper slide pins. Replace the coolant.

Sounds like a find. Do the work and have fun when you use it.

Not a motorhome, but I once bought a Chev P-up that was about 9 years old and had around 12,000 miles on it. The guy used it to tow his 5th wheel and only drive it in the summer. It sat unused and un-started every winter for nine years. I never had more problems with any vehicle in my life and all the problems were caused by the lack of use. I can't even remember them all. Had to rebuild the tranny, replaced head gaskets, brake drums got out of round and had to be replaced, rebuilt the carb, and those are just the things I remember. There were other things. I ended up putting way more money into it than it was worth.

5700 miles after 7 years can be a good thing or a bad thing, do you know if they at least started the motor often, how old is the gas in tank, any oil changes, even though its low mileage still good to change oil at least 1 x per year, check the nada price and than offer lower because you will need to bring it up to par as to oil, rubber, seals, a/c repair, generator might have bad carb if unused, etc, etc, low ball or walk, that's what I would do..