A couple of thoughts Jerry -

First: You indicated that you were familiar with several of the choices on your European tour bus - is that important? I think for a bus load of Non Americans it would be important to have some of your musical expectations met - cowboy tunes in cowboy country etc.   Should you perhaps get some input from Non Americans about what songs/tunes they associate with America and then try to include some of those to help meet the foreignors expectations?   It may be that the Germans and Austrians are as sick of the Happy Wanderer as we are of Yankee Doodle - but in order to accomplish what you want perhaps that is not a reason to exclude the latter. To some degree while you want to be instructive you need to have some hackneyed stereotyped music on that bus.

Second:I do think it is of some value to use a fair amount of pretty well known material and only occsionally use something arcane. That being said as a string band player I'd love to see a few of those old mountain tunes in there but you would have to be very selective - there are definitely some that could work, but many of the potential bus tunes that come to mind are more Pop music/broadway than roots music.

Third - I would try to have as much music as you can that relates in some direct way to each State, major City, major river, or other area your bus is planning to go through - if there is any well known music that fits the bill. If there isnt you can fill in with general "This Land is your Land" "America the Beautiful" and "God Bless America" type stuff . You're going to need a lot more than 1 tape if your driving for more than a coupple of days so you would probably need to regionalize it.

A few examples of the top of my head, based on content primarily, could be:

California - California Here I come, If You're Going to San Fran, I left My Heart in SF, San Francisco Nights (I'm sure there is an LA tune out there somewhere), Lodi (great bus song - Oh Lord stuck in Lodi again)

New York - New York New York, Sidewalks of New York, Erie Canal

Texas - Yellow Rose of Texas, Remember the Alamo, Luckenbach Texas, El Paso, Streets of Laredo, Galveston

Oklahoma - Oklahoma, Okie From Muscogee
Tennessee - Chatanooga Choo Choo, Memphis, Nashville Cats, Ballad of Davy Crocket, Tennessee Waltz, An Elvis tune if you're near Graceland (or Tupelo Miss. I guess)

Pennsylvania - Philadelphia Freedom (yes its by Elton John but..), Allentown,

North Carolina - Tom Dooley, On Top of Old Smoky?

Michigan - something from MOtown,

Mississippi River - Proud Mary

Oregon/Washington - Roll On Columbia

Louisiana - Lady Marmalade, Battle of New Orleans,

Wyoming - Good By Old Paint

Montana - Get Along Little Dogies

Kansas - Over the Rainbow, Wichita Lineman, The Atchison Topeka and Santa Fe

Georgia - Georgia on My Mind

Colorado - Rocky Mountain High

Missouri - Shenandoah, St Louis Blues, Going to Kansas City

West Virginia and Western Virginia- Country Roads

Southern States - you have to play Dixie somewhere - either near Richmond or in a cotton state. Other Civil War tunes may be good specific sites.   Battle Hymn of the Republic should be used at an appropriate place as should America I suppose (Washington DC?)

Many more states and regions to be accounted for. As indicated in others notes using music written by local composers is certainly also something to mix in even if the content doesnt necessarily relate to the area.   Concept music like familiar movie themes from certain settings (like westerns) would also work.   If you go to Charleston you got to have a Charleston ...,

This is too long..