We are looking to make a 'practice' run this Spring, making a cross country trip for 6-8 weeks. It could very easily lead to a full-time period, depending on how it (and some work items) works out. ...
Indeed laundry on the road is more expensive without onboard units of your own. However to go to the extreme of buying new clothes and shipping clothes here and there is more than extreme and if you really figured that cost you'd find out...doing a couple of loads per week is a better option. With a teenager along...well the rules may have to change...no huge wardrobes to take along and no frequent changes..That's about all you can do.