Congrats on the new tt!!! Make sure you get all set up correctly with a wd (weight distribution) hitch, helps even on smaller trailers. Learn how to adjust it yourself. Some dealers will get you close adjustment wise, but once you load it you may (probably) need to readjust it.
Here is a thread about 10 must haves
. While you have a sewer hose, buy a better one (and longer). I have a Camco Revolution (I think it is), has worked pretty well so far. 2-10' sections, and a clear 90* elbow kit. Consider the 5" fence post sleeve mod for your sewer hose. A lot easier to store the hose than stuffing the it in the bumper.
30 amp ext cord
Surge guard- I still need one!!!
Extra water hoses- think I have about 135' total. Couple t's w/ shut off
Awning mat- personal preference if allowed in the cg
If you camp in cooler/ colder weather, electric heater if your site has electric- saves propane!
Fire time- buy a set of tongs and a poker for the fire. Work a lot better than a hot dog/ marshmallow fork! Lol
Fire starter- if you eat bacon, save some grease for camping. Pieces of paper towel w/ bacon grease gets a fire going quick!!! And is a lot cheaper!
Some more leveler blocks for under the scissor/ stabilizer jacks & tongue jack.
Do not be tempted to put a bumper mount hitch on for a bike rack. Does not usually end well. Though there is a new bracket that will help reinforce the bumper, a frame mounted hitch is proba my still more secure (have not seen the new brackets except online pics!).
Water jug if you don't have water hook up.