Time to take a road trip? I dare ya! Make sure while doing it you run the battery to empty to get over the fear of what happens. Just don't do it whilst climbing a mountain
Ideally about 5 miles before you know you'll be stopping for a charge.
The only down side is unless you have it coded - you won't have choice of when that will be. Here in the UK we use our REXes all the time and drive all over the place. There's at least 4 people I'm aware of doing 100+ mile commutes. The only downside I experienced was pulling up at the lights after getting off the motorway - the REX stayed on and wasn't just "put-putting" like normal, it was "Waaaaaaaaaa", probably about 2k rpm. I was hiding under the passenger footwell in embarrassment! No restricted speed despite doing 70mph for about 10 miles after hitting the REX trigger on point. Including a gentle climb for 2 miles to where I left the motorway - hence why the high revving - probably got SOC to 3.5%. Maybe just above the restricted speed kick in.