If this is your first time, and you only get one table, the cart part is maybe overkill, but depends on how heavy what you are bringing to sell is. If you are just bringing a bunch of light boxcars, hauling them into the hall in a few boxes is probably as easy as going with a cart. If you are bringing heavy standard gauge engines, you may want a cart no matter what. 
On a similar note, depending on how much you wish to display, having some small shelves to be able to have more to show can be a benefit. I purchased a small 4 level plastic shelf at one of the home stores (meant for garages/storage rooms), and use 3 levels of it (4 legs and one shelf per) to create small "tables" that sit along the back edge of the table itself. this allows me to put items on the table itself, and then put some other items on these shelves so they can be seen. Of course this could be debated a little, as the shelves do then hide a bit of the table surface, but you can certainly at least still use it for storage. The size of the TCA "table" is 6 feet, but the physical table may actually be bigger. You have the area between the tape marks before your neighbor's table starts. This is important if buying such a shelf, as a 2 foot wide shelf will just fit 3 wide across the table space. Unfortunately I just looked on-line and didn't see an obvious candidate for these dimensions, so maybe they aren't made in this width anymore? I know I bought it at either HD or Lowes.
Since you are not returning to a previous spot, I don't think you will get your table info until all registrations are received and they mail badges. I just mailed mine yesterday as I forgot about the small note buried in the notice that they wanted table holders to snail mail (or sign up on line) by 8/24. Your table will be assigned based upon what is available once they process all the returning members to previous locations.
I'd add large garbage bags if you want to protect whatever you are bringing form the elements if it rains. This is possibly even on your list form being a buyer in the past, but IMO it's more critical when bringing a huge amount of stuff in or out of the meet for setup/takedown.
Evaluate for your vehicle what will work best for you for packing up your items for transport. A few boxes from the local U Haul store may be worth the investment to make life easier than winging it.
Bring post-its, tags or labels and markers for pricing items, depending on what you are selling. Tags being better for unboxed items, post it's being handy for a boxed item.
In case there are slow times, bring a few OGR or CTT to read when the hall traffic slows down.
Those are just a few off the top of my head.
-Dave
