Virgin Campers - HELP

We're getting ready to take our 'virgin' trip with our new 2003 TrailManor 2720 - any helpful hints on what we should stock up on for supplies or what gadgets and accessories we should be sure to take along???  We're not going too far from home (or Walmart) on this first trip and will only be gone 3 days - gotta practice up for this summer and figure out what mistakes we'll make first.  I'd appreciate your hints and good wishes.  We sure are excited . . . it has been so hard to keep staring at it in the garage for over a month now, waiting for the weather to warm up and dry out a bit.
Anxious to get going!!!  (We'll be 'hooking' up in an RV campground - not ready to drydock yet - lol) ??? ???