I have a 2008 35GS so all I can tell you is my experiences. I have never needed pads for the levelers even when in grassy areas so I'm not sure if those are a necessity. As to the surge protector I use the portable, I have seen pics of what happens to one if there is a lighting strike and I wouldn't want that damage anywhere inside my coach.
As to tire pressure, I think the best thing to do is have it weighed loaded the way you would normally travel and then go to the pressure chart for what ever tires you have and adjust accordingly. That is what I have done and the coach rides and handles very well. The door sticker called for 95 all the way around and I am running 85 front 90 rear.
Can't help with a compressor since I don't carry one. Tires have never lost air while traveling.
Enjoy your new purchase.