Anything over 12 miles is normally considered long. Anything under that is short. You don’t really realize how short walking 8 miles is until you do it. You can do a 12 miler in under 4 hours easy, we had to do it all the time. We actually had to do 12 miles around 2 hours and 30 minutes to get a perfect score, but that’s with a little jogging thrown in, and of course that would add to the back problems. When we did our once a year 26 mile, it typically took all work day. A quick suggestion, if you want to do a long one, place about 6 water bottles (doesn’t matter if it’s your own personal bottle with tap water or store bought bottles like aquafina) in the refrigerator the evening (not night) before you do it. I would normally carry 6 to 10 cold bottles of water, some hand towels, and a couple cans of ravioli (You can use whatever you want for a snack, but I advise taking something to eat to keep your energy levels up). Don’t drink and Gatorade or Powerade like drinks before or during the march, regardless if it’s a long or short one. Drink a Gatorade like drink about 2 to 4 hours after your done, to keep the salt/electrolytes from rushing into your muscles and giving you a charlie horse later. I would also suggest wearing silk dress socks under your regular socks, they help prohibit blisters. You might want to clip your toenails too. I know I’m throwing alot of information out there, but I’m a Diabetic and I can do these easily, so don’t let the length of your chosen road march scare you from doing it, I always think to myself how there was nothing better to do that day anyway, lol.