I would approach the dealer from the opposite direction. If they want you to buy the trailer then they should be willing to include the coating and the $10 in Scotchguard at no cost. While you are at it get them to include a LCD TV and include the batteries and an awning and any other extras.
Once a dealer or their salesperson has a live deal and they have already calculated their profit/commission, it is a good time to ask for free items. They are looking at a profit that is a lot larger than what they will lose out on by giving you something.
A $2600 warranty would tell me that the dealer has no confidence in the RV in the first place. I would guess that replacing the furnace electronics and the fridge and inverter would in total cost you less than $2600.