you've come to the right place here. the Tdub will do highway speeds, but that's not it's real sweet spot. there are numerous threads regarding different sprockets and the pluses/minuses from them, you may want to read them and help you decide.
that said, there are also numerous threads of long distance trips, and plenty of smiles per mile. the Tdub isn't a speedy cruiser, but it's a damn good bike that will get you more places than almost anything else will.