Hi Tim,
Welcome to the Heartland Owners Forum and Family. We have a great bunch of people here with lots of information and all willing to share their knowledge if needed.
The PDI is very important, so take your time, inspect everything, make sure everything works and you can work everything, from hooking up water and tv to draining water from all the tanks and with no leaks. If possible stay the night at dealer or close by so you can operate and check everything without the dealer looking over your shoulder.
This is a link to wiki on the forum with some good PDI check list.
Jim M