Something to consider if you are already going to have power on your cart is to have the ability to charge your driver station while waiting in line. I know from experience this can be a life saver with close turnaround matches, especially if you have an older laptop with a dying battery.
It is a pretty simple project, just splice one of
these into your setup so it gets 12V, then plug the laptop AC adapter into one of
these. Connect the 2 together and you are set. Alternatively if you have a universal laptop adapter you can keep with the cart that is even better. (Also, a place to rest your OI on the cart is nice)
(I also have to mention, when designing carts people always forget about wheels, pretty much the bigger the better with the huge cable covers FIRST uses.)