Originally Posted by
Fechten
I live less than a mile from work, but due to being on opposite sides of an interstate it looks like the safest route is about 15 miles (nearest overpass that doesn't have on or off ramps). The area where I live is fairly flat, with the largest change in elevation being the overpass itself.
Well, that sucks. Are you sure that is the only route? Google Maps, with satellite view, can be a great way to scope out alternate routes. Also, remember that any underpass or overpass should do; you don't need a sidewalk. (You know that sidewalks are death traps for bikes, right?)
As for what bike you use, if you're constrained by money at the moment I recommend just borrowing one. Did you have a bike when you were a teenager? Is it still in your parents' garage? Get them to ship it to you.