I have used this twice now:
PDI formI highly recommend reviewing this form and using it as written. A thorough PDI should take you about 3 hours. Do not sign the papers until the PDI is complete and any items you find are corrected. I suggest emailing the Form to your dealer and explain that you will need a 3 hour window to go through the entiree Form. They will need to have water and electric available. Bring tools and a flashlight. Open up every access panel where ever there are plumbing fittings and inspect for leaks. Bring someone with you to help and leave the kids at home (if you have any).
You will find items that need fixing/adjustments and will have much better results getting these items dealt with before you take delivery. Once you drive off the lot, you will be much less of a priority in the dealers eyes.
Good luck