With all this obsession over the ability to get down the Interstate here's something to think about...
There is approximately
4,071,000 miles of road in the United States, of which 2,678,000 are paved leaving 1,394,000 unpaved.
Of the paved roads only 46,876 are Interstate leaving 2,631,124 miles of non-interstate paved roads. While there are many non-interstate two and four lane roads out there where you need to be able to run at a pretty good clip I'd venture to bet that the vast majority of the non-Interstate roads are perfectly suited for 125cc use.
The non-paved roads, on a lightweight bike, open up all kinds of possibilities as well.
The bottom line here and my point is that by slightly adjusting your routes you can go about anywhere you want on a small bore motorcycle. I've been doing it the last five years and you can, too.
So many roads, so little time. Get out there and RIDE...