Motorcycle upgrade options from a 250? From your experience?

I've been riding dirt bikes for a few months and my first bike has been a Honda CBR 250r. I've put just over 2000 miles on her. I sold it now and looking for a bigger bike that can help me get better into street riding. I'm very safety conscious and yet feel that a race replica bike like the 4 cylinder 600cc's are not wise options especially this early into my riding experience. Mostly because I will be using the bike to commute, and ride inter-city/freeway/ and highways.

From your experience can you share your opinions on middle weight street bikes that can be solid for commuting around the city and carving canyons and that can be beginner friendly?

My 1986 Honda Nighthawk 450 was great for commuting and so was my 1985 Yamaha Virago 700.
Wear a full-face helmet that fits.

The next step up from a 250 is 500-650cc. Yes you should avoid 600cc supersports, but not because of their size/weight but the type of bike they are. But there are 500-650cc 'standards' that are still very sporty, fast, good-handling, etc. Like a Suzuki SV650 or Ninja 650.

And fours are not out of the question. They have some advantages over twins. A Yamaha FZ6R, for instance, or Honda 599, bikes that share their engines with their supersport brothers (R6 and CBR 600 respectively). I hear a lot about the new FZ07, that wouldn't be too big.

There are a lot of new models coming out, just in the last couple of years, that are between 500 and 700 and meant as primary trainers. I forget the model numbers but those would be nice.

A 250 will run at freeway speeds but you've probably learned yourself it's not ideal for that speed. An SV650 or Ninja 650 will cruise the freeway more fearlessly and stably.

And any of these bikes would be delightful on a twisty mountain road!

If you like dirt bikes, you might think about a "Dual Sport" bike like a Kawasaki KLR-650 or a Suzuki V-Strom 650.

Personally, I'd go for a mid-size (600-900cc) cruiser style bike like a Honda shadow 750, or a Kawasaki Vulcan 900. These bikes have plenty of power to keep up with freeway traffic but won't overwhelm you like a 600cc crotch-rocket can.