Most dealers will walk you through and want to sell more things to you during the walk through.... like a new pin box, awning toppers, etc... the person walking you through can not tell you what every switch is for. Then they will want have you sign and send you on your way. Once their walk through is over just tell them you are going to check EVERYTHING out and you will be in later.. Take your time, it should take several hours to go over and look at everything. Be sure there is water available and power. If it isn't hooked up, tell them you will need it hooked up to test it, before you sign anything. Always ask for a morning appointment to pick up your unit. If you are forced to a afternoon one, let them know you will want to stay on their lot overnight to check it all out and will need to have a water, electric hookup before taking delivery.
We showed up to the dealer the day before our scheduled pickup day. They had the unit in the shop doing all the prep work ( 3 techs were working on the unit ) and some minor repairs that they had found when they were checking the unit out. This let us know that they actually did test and do a full prep to the unit. When the walk through was completed our dealer, they said the acceptance is on the kitchen table, after you go through the unit, if everything is fine you can sign the acceptance, if something is wrong, let us know and we will take care of it.
Bottom line, take your time. It's YOUR money, YOUR investment.
Did the dealer catch everything? Did we catch everything? Answer is no. But, that is why we bought a Heartland... They have stood behind the product and took care of all our needs since the purchase.