1) You might want to ask this question in the Touring forum:
http://www.bikeforums.net/forumdisplay.php?f=47
The Long Distance forum is more for centuries, double centuries, brevets, 24-hour races, etc. like the description says.
2) Have you ridden with 100 pounds of backpack before? I'm guessing you'll get to the end of the driveway on the first day before you turn around and change your mind about that method.
3) Why would you need to ride with 100 pounds of backpack anyway. If you ask in the Touring forum, you'll see that many of us tour comfortably with much, much less than that.
4) We have no idea if you can manage 30-40 miles a day because we have no idea what you can manage now. Definitely go to the Touring forum and especially have a look for the "are you mentally prepared for a tour" thread. It should still be on the first page.