Sounds like it will be tough but I'll say you will make it.I know what you mean about find time to train.I can only ride Wed and Sundays so its tough to get ready for events.I've heard you can ride 2 to 3 times your base.At 17 miles as a base is cutting it close.If you could get up to a few 40 or 50 milers before hand I say you would do great! Spinning a high cadence in smaller gears works for me.I rode up to 50 milers getting 'ready' for a century 2 years ago.By the last 15 miles I was spinning in the lowest gears on my 21 speed and I mean the lowest.I went to the ride by myself but met a couple other riders that were about my skill level (terrible) and that helped a bunch.It was getting dark when we chugged in to town,but we made it.Hope ya do it ,MS is a good cause...KC