We did purchase 1 DP from PPL Houston. The process went very smoothly. They have a list of things that must work before the coach can leave the lot. That list does not include leaks or water intrusion though. All the safety features must work and they have other items also on a checklist. The seller sets the price following their advice a little. They negotiate with the seller for you. We licensed it and paid taxes in SD and that went smoothly also. If you find things wrong, the seller does not have to accept your offer or fix any deficiencies you find if there not on the required list. They have some nice units and some you have to look over close. Can't answer about flood units, except to look them over very close. All in all, out experience was good, and we only had a couple of small surprises to take care of after the purchase. We did not trade in a vehicle. Hope this may help, happy trails bert