The best thing you could do is take a small (overnight) trip to the a local campground and bring a pen and paper. when you get home you will have a very specific list of what you need to bring next time.
Also, assuming you have a Weight Distribution Hitch and other towing essentials, here are some things that are specific to Travel Trailers vs tents:
tank cleaner,
gloves,
boards to level side to side,
potable water hose, ( PLEASE..GET A WATER PRESSURE REGULATOR ),
wheel chocks,
a good level,
This like most others is not a complete list.
Congratulations