Have you ever tried to sell something on Craigslist, like a car, boat jet ski or snow mobile. You get a dozen requests by what I call "Craigslist Cruisers"....they ask a stupid question like....what color is it when there is a picture on the post. You answer and never hear back. I'm sorry, but you're emailing with the list of questions and instructions would immediately send up a flag that you're more about asking questions than buying....a five year shopper.
I would call PPl, make a contact and then email them your questions. Personally, you're asking a salesman to spend hours looking at three different coaches and then replying back to you on each one. Now, that brings up another issue....his idea of really clean may be your idea of a piece of junk. He responds back, with an email that the coach is really clean and then you fly in and accuse him of lying about the condition. Just too many issues to provide the detail you ask for, unless you can prove that you're a more interested buyer.
Lastly, your unwillingness to make a few phone calls to make that personal contact tells me that you really are just shopping and don't want to get involved with a salesman and make a commitment, the same thing you're accusing them of.