I have had my Clarity since the end of January but used it mostly for commuting to work (~20 miles) and short errands, almost all EV except short freeway segments. So I was excited to take it to its first long trip, 300 miles to Vegas. I filled the tank and charged full overnight. It gave me a range of 62 mi EV and 336 HV to a total of 404 miles total range. I started as usual in Eco mode and it ate like 10 miles EV range while getting to the nearest freeway 4 miles uphill. Then I hit HV and Sport to merge onto the freeway and kept driving between 70 and 75. I was concerned about charging in Vegas since I didn't know if I would be able to charge there, but to my surprise the EV range seldom went below 50 except when climbing up to Halloran Summit, and even then it only went down to 47. However, arriving in Barstow the tank was already halfway down so I refilled there (blessed hybrid). Anyways, upon arriving to Vegas the tank was already halfway again but the battery had still 50 EV miles! On the trip back, my friends allowed me to recharge so I went back to my 60 usual EV miles but when filling up at a nearby gas station, HV miles went up to only 282, leaving me with only 344 miles total range. I arrived back in Barstow with half the tank but still 52 miles EV. However, when leaving the pump, I forgot to reactivate the HV mode before hitting the freeway, but thankfully my sweet wife somehow noticed the EV miles on the display had gone down to 17 in less than 5 minutes! After switching to HV, the charge remained steady and even went up a couple of miles when I hit SPORT to pass several vehicles. I arrived home with 17 miles EV and 2/3 of the tank remaining. Strangely, after recharging overnight, I only got 52 miles EV range instead of the usual 60. Fuel economy was somewhere between 42 and 43 mpg. Take home lessons: 1) NEVER FORGET TO PRESS HV WHEN YOU RESTART AFTER STOPPING TO REFUEL. 2) Don't worry too much about battery charge in long drives. It will keep steady near 50 unless you run too fast or make a long climb, but it will recharge fast on the way down. You just need to worry about gas like with any other car (a slightly bigger tank would make life easier). 3) Range estimations seem to be heavily dependent on the way you did things last time.