Lots of things you could do, some depending on how involved the quilt shops are willing to be. Some that I have been too have each shop give out a block pattern and will make up a quilt using all of the blocks. Do you already plan on getting "shop hop" totes?
Since you'll be traveling by bus put together some games to pass the time while traveling. If the bus is able to play movies you could play different tutorials for those who want to watch. If the shops don't offer, you'll want to see about drinks and snacks and as Maniac, mentioned a lunch venue or a box lunch pick up will require additional planning.
I'm sure it's going to be a lot of work but they are so much fun! Good luck!