Walt, just for my two cents worth, I think if it was me I'd take one of your cars with you. There are just so many variables, being able to whip your car out and plunk it down on the table and hook up a potential purchase to it will immediately tell you whether it's perfect, or could be made to work, or just ain't gonna happen. Otherwise, you'll find yourself guessing. You'll be carrying so much other loot by the end of the day, bringing one car in with you won't be that much inconvenience.
