The tap-a-draft always seemed a little expensive to me. For $70 you could probably get a 2.5 or 3 gallon corny on e-bay, and they're a bit more mobile than a 5 gallon.
I typically just bring growlers over to the neighbors. But if they run out, I can dash home across the street so it's not that big of a deal.
Unless you're willing to build something like a portable cart, your best bet just might be a rolling cooler.
Ain't nothing wrong with a little redneck every now and then.
I did the trash can thing just this past weekend for our block party. I had it on a furniture dolly with the gas in a milk crate. Everything held together with bungee cords. It was redneck but effective.