Congrats on your new ride. I like everything about maxi scooters except that the CVT keeps them from being super fuel economical, but they are super practical with all that luggage space and weather protection and one just pulls back on the throttle and goes. Didn't like how quickly mine ran through tires, especially the rear although I'm not sure If I'd ever been brave enough to try a car tire on it for wet weather safety traction reasons. The Piaggio also had sort of weak brakes as compared to my motorcycle that was noticeable only slowing from highway speeds. But that scooter was very quick and nimble and good mpg for its performance level.
Surprised at your great mpg on a maxi scooter; even for a 250, that's great! But hey, it is one of us riding it, and it looks more aerodynamic that my Piaggio was, which was a rocket for a scooter up to 80 mph
.
The best I ever got on my Piaggio BV350 was around 71 mpg in an ideal commute situation in a rural area along state highways and one small town. I'm also only 5'8 and 145 pounds, so that helps me as well. My low on the Piaggio was around 63 mpg. Speeds from 45-65 commuting. I think that my average was 67. I had it for just over one year.
My Honda CTX700 can achieve 78 commuting in the Summer but; have achieved 85 on a short, two-way trip (but average 82 on such trips), and 97 in an FE contest. On average, it drops much more in the winter than did my scooter; going as low as 70 in regular commuting at or below freezing. It took me a while to get used to the hassle of trading a left hand brake for a right foot brake, as this is my first bike, and it'll probably never feel as intuitive for someone who didn't grow up riding motorcycles.
Are you solo 100% of the time? I did something on both my scooter and my motorcycle that most riders wouldn't dare do because many are worried so much about appearances and trying to convey an attitude over practicality. Instead of having a top case on a rack well back behind me leaving that huge gap that always looked to me as a drag enhancer, I just strapped a rectangular box directly atop the pillion portion of my seat for reduced drag and more efficient and spacious luggage and better handling. In fact, if one could construct his or her own-styled box, taper and then cut off at the correct distance and angle, one can build it to create sort of a streamline effect as Sendler has done on his CBR250R. But I don't know if your set up would allow for a solid tie down in the simplified version that I was able to do, but I'm sure it's doable without too much trouble.
On my Honda CTX700, I run a couple of one-inch-wide lashing straps around my seat and hooked in an area under the seat where they can't slide, and an additional tie in the very back, as it is a long box. I could, if I felt necessary, tie to my tie-down hooks as well, but it's plenty sturdy as is. I've had three different boxes on it that way (a 42 liter top case, a 55-liter Dewalt tool case, and currently a large, rectangular milk crate with no top). These boxes and cases do not reduce mpg at all as compared to stock without a case or rack and it doubles as a back rest. I laid the bike over twice; both times with that big Dewalt box on there as pictured below. The box never moved. And no...the box had nothing to do with my layovers. Once was a bonehead move on my part, and the second was bonehead move on a cager's part that was virtually unavoidable at my skill level.