Thanks for the information. I plan to use a service catering to fulltime RVers that give a mailing address and physical address, so hopefully I'm covered there.
Unfortunately in my brokerage account I have Vanguard mutual funds, not ETFs. I guess they don't care about buying and selling ETFs(?), but I'd have to come up with a way to move VTSAX to VTI while minimizing capital gains, or I guess just pick the mutual funds to sell off first as I retire and need to draw?