For a single, not-too-big rider, a 250 is fine. I commuted for more than a year on my Ninja 250R, and I’m 6’4″ and almost 200 lbs. Not only is it totally fine getting to freeway speed quickly, but it’s also perfectly capable of gunning up to 80 to make a pass. It’s easy to be spoiled after riding a bigger bike, but the Ninja 250R is about as capable at legal speeds as my car, and while it’s no Maclaren F1, it has 265hp.
It’s another thing to ask “could you be more comfortable on a bigger bike?” It’s another thing to ask “is it good for long-distance touring?” But is a 250 “freeway capable”? Absolutely!