We won't be able to file the N-400 for about 6 months yet, and a good bit of that will be out of the country, but is there a domicile requirement for the N-400? And what would be acceptable as proof of that? We're full time RVers, so addresses are kind of difficult. My mail goes to a friend's house in Ohio so we have some financial docs that have that address but do they need more, like a lease?