I'm about 140lbs and the 250 doesn't have a problem of hauling me around, even over 75mph. Of course, it doesn't have the instant power compare to my 600RR with 520 conversion and -1/+2 gearing. However, it does have enough power to pass cars at average freeway speed. "Enough" is subjective and expectation varies. So, have fun and don't expect too much. :)

I'm 125lbs. and no worries. Of course my bike is badass. With my full yosh and jet kit the bike loves high speed and high rpm and I don't have to downshift to pass. I was weary of the freeway at first but it is my first bike and I got over it. The wind can push me a bit but I just push back.

I think the wind is an issue with all sportbikes. I had the same issue with my old F4i on the freeway, but learned how to deal with it. The smaller rear tire on the 250 does make the bike move around a bit on the freeway, but nothing major.

Would uping the tire to a 140 in the back help with the moving on the freeway? (first bike, so not sure!)
I ride my bike (when its not in the shop :() on the freeway to work all the time. Rides in the fast lane just fine imo.
Im 5'9 and 175 lbs btw (fat!)

Definitely help in stability if you have bigger tire in the back. I think 140 is as wide as you can go without rubbing the chain cover.