2016 TDI Lux, white with beige interior
You only need 2.5 gallons at a time. Or pull into one of the good stations that have DEF filling nozzles.I'd hook that to my "fixed" TDI Exec and take it to California without any concerns. YMMV.
If you're going a long distance, pack 10 gallons of DEF and keep your trunk accessible. Enjoy the ride.