Not much help but..........
Hi Janet,
I can't help much with this one other to say that you would be better off e-mailing the tour company regarding Rainbow bridge and get an itinerary straight from them. As the bridge is the whole point of the tour I can't see them not allowing the time to walk there and take pics etc. I would imagine the half hour is for the purpose of standing there and admiring it, taking pics and not including the time for the walk.
I like to buy a seperate map for each State I visit as I find them more detailed than one that will cover larger areas. AAA do reasonably priced ones.