Thanks everyone! I'm feeling more inspired. I wasn't sure if 35 miles will be a daunting task in a short span of time.

I test rode a road bike yesterday, (Norvara Camara Pro), and whoa...it's a heapload better than my crappy 10 year old Schwinn bike. Mind you, my bike still works well and I think it still has a lot of life left (aside from the stupid gear set up...you change gears like a twist on the handle bars...not exactly very easy to use), but it does leave me struggling to ride. I am doing the best I can, and get the miles going, then I will decide on a bike in about a month. I'm taking training classes specifically geared towards the 35mi charity ride. But, I rather learn about the saddle fit, bike size, what to look for, etc before getting the bike. I don't want to turn this into "not another 'what bike to get' thread", but frankly, I'm kinda stuck on choices because I'm 5' and I think I'm roughly 43cm...that doesn't give me a whole range of bike to choose from.

Anyways - thanks for the encouragements!