Keep in mind,
I'm 25 years old
Currently Active Duty in the Marine Corps
and my 3 mile (run that is) is roughly 20 min.

With all of that said could someone bike 100 miles in one days worth of riding? With that how long would you recommended riding in one day? When I think of me riding a bike for like 10 hours I don't cringe at that at all.... then again, thinking about and doing are two totally different things. I know there are also lots of factors that go into this whether your going up hill or going down hill and pavement or off road. I'm asking though in a perfect world and then I can fluctuate on that. Also I understand that I need to get out and learn my potential before really getting into this. Just want to know what I should think of as reasonable. As getting out there and actually riding my route will probably be a lot different then riding around my town and local areas for long distances.

Edit: Is there a place on the forums I could post about possibly borrowing a bike from someone just for training rides. I plan on getting my bike back home and riding it down this way. So I would only need it for training.