Figure on a hotel room (or 2, depending on how many are in the band) every couple of nights for showers when you can't mooch off of friends.
And when you can't shower every morning, a change of clothes (clean ones!) is really neccesary, so have a couple of rolls of quarters ready for laundry.
Road food can take its toll, too - try to eat healthy, ask folks ahead of time for restaurant advice so you're not stuck with fast food and bad pizza all the time. Stop at good grocery stores for salad bar meals or for ingredients to make a decent meal (potato or pasta salads, etc) Places like Whole Foods have big hot/cold bars with healthy choices, and when you think about it, it really is no more expensive than fast food.
Of course all this is moot if you get one of these new RVs for touring: http://bottomline.msnbc.msn.com/_news/2 ... llion?lite