We found a 5th wheel toyhauler that we really liked nearly 900 miles away. It was a new one and we sent them $1000 as earnest money.
We drove down with our old trailer as a trade-in. We did an 8 hour PDI and were prepared to turn around and go home if all didn't go well. We were pretty sure it was all good ahead of time, but we insisted on a thorough PDI before we turned loose of any more cash. They fixed all the minor issues, put on slide toppers at a good price, and we paid for our new trailer. Everybody was happy.
Research will only take you so far, and then you need to see what you're buying. Money is too hard to get to risk $10-15,000 and get burned. Shoot, you hear of people getting burned buying face-to-face from a dealer, I can't imagine buying something sight unseen. Just the way I am. My dad said to never buy a pig in a poke.