Hi There,CJ7Boomer!!!
Long time no See!!!!
You will love Montana...so will Lou Dog!!!!
Just don't let him run off in those Huge Fields,Mountains and Streams!!!!!
I've driven dogs (&horses) to All 48 States.....Never had a problem with a dog....from where you are it is 2 to 3 days..with 1 driver...2 days with 2 drivers....dogs usually just curl up on the back seat and go to sleep...unless you know he doesn't travel in car well...they don't know how long the drive is...

Just use the rest areas to walk him....DO NOT LET HIM OFF LEASH at one of those....he will find all new smells and could run off....Too close to highway...
Just make sure he has Water at all times....you can use one of those bottles sold at petsmart that joggers use....or the collapsible ones are good too....

if you are going to stay in hotels and not drive straight through....find out who allows dogs before you go...and how much they charge and what Weight dog they allow...there is a website....something like....petfriendly.com....that has complete listings!!!

When are you going????
where are you moving to????
Good Luck.....Get back on Pet Talk soon...and let us know how you both made out on the trip!!!