What you really want is a copy of the service records for the vehicle. Make sure the oil, fuel, and air filters have been changed on schedule. On the HydroHot, make sure it has been serviced. Once a year is recommended.
Check the chassis and engine batteries. Find out if they have been changed since the coach was purchased.
Tires are due for replacement if they are original to the coach.
On the house side, check the wet bay floor for any sagging or rot. If it looks flat, try poking a screwdriver in it. Same thing for the driver's side main slide. These items may be covered under a Tiffin extended warranty. You can call Tiffin with the VIN number and see if the coach has ever been in for repairs. I don't believe 2007 models had issues with roof rails, but ask Tiffin about that as well.
Roger & Mary
2017 Winnebago Navion 24V (Sold)
2014 Tiffin Phaeton 36GH (Sold)