Riding my stock Lifan 125 powered step throughs and K-Pipe is a hoot. Around town they have plenty of power and on the 40-50 MPH streets they have plenty enough speed to keep from being run over. The Passport with the 141cc kit and cam is even more fun and regularly impresses people with how fast it is light to light.
Occasionally I'll hit the in-town interstate (50-55 MPH) for short distances if I'm in a hurry and while I'm the slowest vehicle out there so far I've not been run over. Yet.
There are lots of guys on the hondagrom.net website who regularly get on the autobahn with their bikes. They're very brave.
Me? I prefer to travel on the backroads and old highways. I feel perfectly safe traveling the roads that were left behind when the interstates came along and obsoleted them.
For those with interstate addictions small bores ain't the ticket. For everybody else they're a hoot and a nice alternative to riding a heavy bike. I haven't straddled a big 'un in years and don't miss 'em at all.