Well I finally did this trip yesterday and it ended up going surprisingly smoothly. I charged to 100% in Farmington and initially the nav said I would make it with 11%. Shortly after I left it was down to 8% so I started getting a touch nervous. Fortunately I found a truck going 70 mph to draft behind in the early part of the trip and pretty quickly it was up to 21%. Eventually when I was really comfortable I took off on my own and pretty much drove 75 mph the rest of the way. I rolled in with 18% left and my Wh/mile for the 181 mile trip was an impressive 292, which for my car is incredible. Nothing to worry about!