Roadshow venues are booked three months at a time. Although this can be a challenge for a new venue, the reason for it is that it avoids a monthly scramble on the part of the Agent and the Driver to confirm a venue again -- once you have a booker in front of a calendar, it's better to take care of it all at once.

What the Driver will need confirmed is the date, time, venue, venue address, local act and cover price (if not pay-what-you-can -- up to $5), ie:

PITTSBURGH: Monday, Aug. 15, 7pm. Garfield Artworks, 4931 Penn Ave. $5. With crafty poetess Jessica Manack.

Some tips:

• Venues can vary: bookstores, bars, galleries, punk basements, whatever you think would be a lively place for a show and won't stress you out. A smaller space is generally appropriate.
• Bookers at bars don't generally care how talented or cool the entertainment is, they want to know that there's a good chance that it'll bring in drinkers. Fridays and Saturdays are especially hard to book, try getting a band to be the local act or someone who'll be a good draw. If the Roadshow has gotten press locally in the past you could bring clippings to leave with them--this is a good overview of the project.
• If you book your local acts first, they can give you tips as to places they've performed at and will help you convince the booker that people will come.
• Generally you can assume that the crewmembers will have their own equipment and will not need any special AV needs unless they get in touch in advance. 
• If they want a guaranteed minimum or a rental fee and you can't find somewhere else (though you should be able to) offer to split a cover charge with them so half goes to them and half to the performers. You shouldn't go out of pocket at all.