Four Winds by Thor is an entry level RV. First and foremost on any RV is look for leaks. You need to spend a couples of hours of labor to have a certified RV tech (not the selling dealer) to perform a complete check of all systems on the RV as well as a roof and window inspection for leaks. The cab over area is really prone to leaks on these units.
Also, see if there are good maintenance records for the maintenance on the engine, generator and transmission.
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