Upgrading from a 300cc motorcycle?

I've happily commuted on a CB350 on freeways & highways. The bike would sit on 65 mph all day. A change of handlebars to get your weight more forward helps if you spend a lot of time up around 60mph. I'vehad three 500s, all would reach 100 mph comfortably - How fast do youneed to go?

While riding a CL350, I rarely needed all its power,  myself being under 150 Lbs. When my wife got on the back, I thought I could use a few more HP. She's a big girl. If you're going onto the big interstates through Wyoming and Texas where the speed limit is 85, the CB300 is going to work hard to stay off the redline, but if you're a heavyweight, it could be time for you to promote to a bigger class. Why don't you test ride a few bigger bikes to see what you can handle.

For a short highway commute a 300 should be fine.  If you feel the need for speed, go with the 650.  I have a Rebel 250, and have no problem with 60+ mph on the highway.

 The CB and the ninja are totally different types. You sound more like you need a small tourer. Get a 750.

  Ninjas are Fast, but, have you actually Tried one? Fatigue. Fast.

  Yes most 500s "can" be used on freeway, but, most Shouldn't. Even my cb650 wasn't good for freeway work, over an hour. I now have a 1440cc (88").

   I don't believe in stopgap measures. That "short highway commute" will soon  turn into an hour's pleasure ride on a weekend--and, you'd wished you'd gotten that KZ750. I went straight from  a Honda 90 to a 650 Triumph. The Triumph was fine for an hour on back roads at 55. I wouldn't cross the country on it, no.

a modern 500 CC will run on any freeway just fine. I think its more a matter of what is comfortable to ride. Go sit on some bikes and see how they feel.

Like dude, size ain't everything. You wanna sport bike or a standard or an adventure bike? I prefer bikes with hard cases, meself, 'cuz they hold stuff.

You want to UPSIZE your motorcycle, not upgrade.

A Honda cb300f  can do over 85 mph.  How far over the speed limit do you need to go?

In Los Angeles, freeways on heavy traffic, my 150cc Vespa could out-run anything on the road.  If you want to drive fast, you need to learn how to look ahead, at least a half mile ahead.

Since you ask, you obviously need to get at least a 650.

It is time for a major upgrade.  The CB1000R.