As of a few years ago I know that the Lancaster show definitely did not allow wheeled carts of any kind any longer. They also do not allow food anywhere in the display or vendor areas. They do have a 'food court' per se but finding a spot to actually sit and eat your food can be a challenge. At least it was - they may have changed that set up as well since it's been a few years since I've been there.
I agree with a small notebook of some sort or, if you have a smart phone, use the memo or such app on your phone or even just the camera. DH takes pics of everything from labels to large items that he wants to remember or refer to later.
Comfy shoes are a must! I have really nasty arthritis in both feet and hips. If I know I have to do much walking, I wear flip flops regardless of time of year. The back acts up after a time as well. Take breaks.
And I agree with starting with the vendors if that is part of what you are going for. The quilts aren't going anywhere, lol. Items at the various vendors can be gone in a heartbeat. Although I do think most are fairly well stocked.
Most of all - enjoy your trip! Have fun with your fellow guild members and heed the advice of the veteran show goers.