You can call Motel 6, and ask for recommendations for local tax cab companies.
There is 24/7 walmart on North Gulph Road, you can stock up on groceries or buy prepared cooked meals.
The Raddisson offers their hotel guests complimentary shuttle bus service to King of Prussia Mall.
Last year, after midnight the tables were free until something like 6 am. The year before, they were charging $10 all night. I don't know what time the convention center closes, or if they throw people out.
The Convention Center is situated over two hotels, the Scanticon and the Raddison. There are a couple of dining choices in both hotel, Blue Grotto, Chumley's Bar, etc. You can check the menus online through the hotel websites. On the lower convention floor you can buy burgers, hotdogs, beers, soda, coffee etc.
Another option is delivery, Chinese, Pizza, etc. You'll need to meet the delivery guy at the front.
There are vending machines for beverages, but due to the sheer volume of attendees, they're always running out and often empty when you're dying of thirst. So if you see one that's just been stocked
A final option, forgo the hotel, stay awake all night to watch the action. Buy daily tickets for the Pro matches, find a empty spot on the bleachers and nap there. Its nice and dark, so as long as you don't snore, I don't think anyone will notice. If someone does catch you napping, then complain that match play was so slow it made you fall asleep.