Right - don't I know 95 North/South in CT! I live just south of the CT border.
I have the automatic Clubman Cooper, but it's very new - I only have about 150 miles on it and most have been very short local trips, very local. Right now my mpgs are at about 30, but I'm expecting much better mileage once I start doing some serious driving on the highway, etc. I have heard that this newer automatic does very well and that the cruise control also is much improved - though I've never been a cruise control driver, I can see how on very long trips it might come in handy. I would not at all be surprised to find that using cruise control would help with mpg savings, too.
Of course you are so right about not needing to "fight" to change lanes to get ahead, etc. Just thinking about it can make me feel tired, though I have to admit I've been guilty of it.
Really, if it's only saving 30 minutes, saving one's life is surely more important! Not to mention saving those dollars.
Looking forward to getting to know my new bigger MINI better in the very near future.