Cincinnati-New Orleans-Grand Canyon-Rt66-California-Yellowstone! One month, advice pl

[Sophiest]

Ok, we have a month to see as much as we can on an average budget. We thought we'd drive one way and fly back. We'd like to see New Orleans and anything thats good on the way there, after that we need to find the best route to the Grand Canyon taking in any natural wonders on the way...or awesome cities. We'd like to do a little bit of Route 66 and have heard that the best bit is on the way to GC from Flagstaff. From there, it'd be nice to visit California (San Fran, Napa Valley) for a while and then go on to Yellowstone. We'll be going from mid May to mid June so thought the weather in Yellowstone would be better in June...is this right? We're from Australia and have done some big road trips there but don't know the best things to see here! Advice would be appreciated very much.

Moderator Note: Please do not create multiple threads about the same trip.