My wife is already talking about it like it's going to happen and I am surely tempted. It would be easy to head north to put a foot on the Canadian border to start. I have two real hesitations, timing the weather and whether I really want to put my battery pack through so many SC's, surely I would see a permanent loss in range post trip... then again, it really would be a trip through some fantastic and remote parts of the US.
I've spent some time doodling a route from my home in Maine to Fremont, passing through each of the 48 states + DC without entering any state twice.
General plan of attack:
Portland ME
Manchester NH (charge at Northeast Utilities)
Brattleboro VT (overnight with friends). Various roads through
Worcester MA to
East Greenwich RI (supercharger)
then straight down I-95 to St. Augustine FL, picking up:
CT NY NJ PA DE MD DC VA NC SC GA FL
Then I-10 to Beaumont TX, picking up:
GA (requires a slight detour through Bainbridge) AL MI LA TX
Corsicana TX (charge at RV park)
Hugo OK, US-70 east to
Little Rock AK, then US-67 N to US-412 east to
Kennett MO, then across the Mississippi River into Tennessee, ending up in
Knoxville TN. (This stretch would be easier with the Chadmo adapter!)
Lexington KY
Charleston WV
Columbus OH, then Maumee OH
St Joseph MI (carefully detouring around Indiana)
Gary IN
Rockford IL
Mauston WI
St Paul MN
Fargo ND
Madison SD (home to a Model S Plugsharer), then across the state's SC network on I-90
Gering NE (RV park, but we can't use up Wyoming just yet)
Denver CO
Grand Junction CO (SC along the way at Silverthorne and/or Glenwood Springs)
Farmington NM (top-up charge in Durango CO), then follow the I-40 SC corridor through
Flagstaff AZ to
Las Vegas NV. Detour through Caliente NV (to avoid reentering AZ along I-15) towards
Salt Lake City UT. I-80 E and US-189 N to
Kemmerer WY and Jackson WY, then on through Yellowstone to
Bozeman MT. I-90 W to
Kingston ID
Ellensburg WA, then take the I-5 SC corridor through
Portland OR to
Fremont CA
All told, this would be 9,498 miles of driving. Yikes! (Fun fact: if you're going to do a once-through-each-state trip, you must start in Maine or use Canada.)