" Can I set up Directv (we have cable now) at my current house (which is being sold), take the dish and box along when we start fulltiming, and just change my account address to a PO Box somewhere?"
Yes you can, although its to your advantage to file the DNS waiver with a copy of your RV registration to get the DNS east/west network chan feeds; DTV uses 2 addresses, your billing/mailing address and your "service" address, A POB or PMB is ok for mailing, for the service address they may insist on a street address, or you just pretend your #1234 is an Apt bldg.
"Will Sunday Ticket work without a landline?"
Yes it will work fine. the only thing a landline is required for is ordering PPV via the on screen menu/remote
"Will using an address in a different state set THAT local area as my Sunday Ticket blackout region, allowing me to still receive my home state team's games?"
For most fulltimers, our DTV service address is our mail forwarding address; mine is Box Elder, SD where there are no home games, so I don't recall ever having games blacked out. a few fulltimers who choose not to use the DNS national network feeds, & change their physical service address as they move and I assume that would effect whats blacked out.
