One thing every tuber should have is a repair kit on board, it's small and has everything you need to do an emergency fix.
I didn't see that you git a pfd, if not grab one of cheap orange ones from big 5, walfart, or sport chalet.
Just make sure you rinse off the tube, waders,fins, rods, and reels after fishing, especially the salt.
Also the first rule of tubing, if this is your 1st tube, Never lean forward w/o your striping apron in place, that's not to say you can't lean forward, just don't lean to far, or you could be swimming. Re: the pfd, most of us just strap to one of the straps that attaches to the back rest, then store the pfd in back of the seat.
Also, when transporting your tube, especially on warm days, let some air out of the bladders, as heat will cause them to inflate, unless you deflate it to transport..
If it's your 1st time tubing, you might want to go out with someone that's experienced, to show you how to enter the water, and how to kick, so you get the most go for less work. And how to turn your tube among other things. Well, that's all I can think of at the moment, have fun!