We too bring our own TT. We also generally use the comfort stations too. While they are very clean and nice, I wouldn't classify the "Showers" as "Roomy" but they are more roomy then the ones in your typical TT. They could also spare to have a little more "Hanging" space for your clothes/towels, etc..
Definitely brink extra towels depending on how long you stay (and your preference for towel usage). My wife doesn't like to use a bath towel for more than 2 days in a row. Me I am ok with a week. It just depends on you I suppose. I would also suggest a set of "Beach Towels" if you plan at all on going swimming.
I also suggest a length of rope/cord. 50 to 100 feet is good. You can hang it up to dry bathing suits, towels, Drape a tarp for an impromptu cover, or to tie things up (not the kids though.
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For your toiletries a little carrier is also good. I have a "Shaving Kit" that is my standard, but then again, I don't have shampoo, conditioner, lotion, body wash, body splash, 3 different kinds of deodorant, perfume, multiple razors and shaving cream (you get the hing). I have basic soap, toothpaste, toothbrush, deodorant, 1 razor, small shaving cream, comb and a few medicinal type supplies. It works for camping or traveling for work. Always packed and always ready to go. Soap washes body and hair, and can double as shaving cream if needed. My whole point, is that it's much easier to carry your stuff to the CS with an organized carrier or shaving kit, then trying to toss them in a plastic bag.
A deck of cards can also be valuable.
A word about computers too. While there are some places that have WiFi (pool, lodge, etc) and you can get internet for your site (that have a cable connection) you do NOT get a WiFi Enabled internet kit. It's for a single computer wired to the cable modem. If you want WiFi at your site (for your laptop, cell phone, kids cell phone, tablet, etc...) bring your own Wireless Access Point to connect to the Cable modem. That way all your devices can use it at once.
