After driving my Volt for 2 years and 36K miles with at least 6k of that long distance driving. i settled down of a strategy based on the fact that best use of the battery. Electric mode is best used for low speed driving, gas is best and only used for long distances where I know I will go over my battery only range. I don't have the privilege of using hold mode in my 2011 Volt so I use the next best thing and that is Mountain mode, it al least will give me around 14 miles of Battery that I can hold when we pull off the highway to fill up gas or eat on long trips. Doing this helps overall MPG. When I get close to my destination (around 14 Miles) based on GPS, then I go to electric the rest of the way. In my longest trip during the summer I was able to get 47 MPG (please note that I drive at what ever the posted speed limit is) in a fully loaded car and in some cases 102 degree days. I also learned that the Volt can get up to about 4 better HW milage because of the less dense air. So what I do is as I leave the driveway or over night stop, on my trip. I just automatically put the car in MM for as long as the trip last till I get close to my destination where I can charge the car. I find that in MM that the power usage strategy works a little better then allowing the car to go directly to CS mode. The large buffer of MM seems to give advantages in the overall usage of the battery and ICE. If you end up in traffic on a long range trip, stay in MM, what happens will astound you. The extra battery buffer will allow the car to just turn the motor off and stay off till it uses the CS and MM Buffers. It will keep the 14 miles until you switch out of MM and return to electric only mode. I notice lots of people switch in and out of MM based on only using it for mountains. But as I have described it has a useful features for long distance driving. Since you have a HOLD mode, this may just be what you need, but as I said and my main point is that for long distance You will use gas no matter what mode you pick, and the best strategy is to hold as much battery as you can as it pays off in the long run.