What accedssories do i need for a new 5th wheeler?

I going to purchase a new 5th wheeler, As part of the Offer I make the dealer, I'm going to ask for accessories. The BIG questions is what accessories do i need for a new 5th wheeler? Never Owning a 5th wheeler, I need some suggestions. I have a bumper pull, but is a very basic unit, no slides. Besides a kingpin stabilizer and some levelers for the wheels, What am I missing?

Advice Please.
TIA
Jeffrey