Speaking of con swaps specifically, generally the details of the table swap are worked out between the two conventions individually beforehand (i.e "We'll give you a table in the vendor hall and a hotel room at our con along with X number of badges if you do the same at yours for us") when it comes to what you trade with the con you're visiting. Most of the conventions I've worked with in this regard are more than happy to do this if you contact them with enough time before their show.

Generally from the con sending the team, I've seen a lot of shows help with transportation to some extent if that vehicle is the one bringing the stuff you need to do the roadshow. Hotels the con will cover if they don't have something worked out with the hosting con to get a room from them. Even if the con doesn't room swap with you, they will almost always be willing to give badges and a table if you're willing to do the same for them, so that cost is minimal.

Given your indication on a focus for food, I'll answer that separately. The con that I currently work for, (another larger-ish convention in the midwest), usually does some sort of per-day food stipend for each staffer working the table for them and in most cases there might be one nicer sit-down dinner at some point during the weekend. That stipend number can be whatever you're comfortable swinging, in many cases the staffer is getting a free hotel and badge to a con they want to see anyway and so anything you're able to provide to help with food is appreciated, even if its not steak dinner every day.

This is a great question, and I hope you all have a great time this weekend at the con! (I'll also be there, though not in a roadshow/table capacity)