Months back a person was on here because he had bought a truck camper and gotten it home only to find wet cupboards when he started loading it. He then went on the roof and found the wood buckled under the leaking roof membrane.
I would be in it, under it, on top of it and around and around it and still be nervous.
If you inspect one pre purchase, write down the vin number. My sister recently shopped for a Ford car. She looked at it, drove it and then called the salesman back to say she wanted it. She went in a few days later and signed and drove away. She then found that it wasn't the same car she had driven. It was the same color and SHO package and most of it was the same but missing a couple options that she knew she had seen and used during the test drive. It was a different car.
Tell us more about your plans or if you are buying new or used.