Moving

I plan on making the move to Mx in 11/18.  I know that I need a 6 mo. visa & can then decide (eventually) on permanent resident or citizen route.  I planned on driving my SUV down with my belongings until I decided upon & found where I want to be; then most likely, driving to the US &
& selling it.  My Vt driver's License is good for 2 yrs & the inspection I'll get in Nov. good for 1 yr.
That plan just left a few odds & ends to take care of prior to leaving, most notably $ & banking.  I thought I'd had this solved by adding a Schwab acct. into which I can have certain funds & SS electronically deposited & just use ATM's in Mx with a Schwab card, at least untilI find something more suitable.

I spoke with Schwab yesterday & discovered that G-d does laugh at man's plans (No offense to women).
I was told that I must have a US address listed as one of my addresses (PO boxes won't do) & not having one would make me an 'international' investor.  This in turn would change the type of investment accts. I could have & the investments I could make.
I'm also concerned that it'd open me up for state taxes which I was hoping to rid myself especially since I'll no longer live there.  So I've got a follow up meeting with Schwab & have got to call the accountant.

Any suggestions from those of you who have been battle-tested & have gone through this without a US residence listing.

Another question, any advice on finding a mail service that works and copies & emails you the letters, bills & whatever?

Thanks,
Dukie