Thanks all!
I think I lucked out with the weather, a lot. I kind of enjoy running in a warm rain, don't much mind it when it's above 50°, but I realized last night I'd never, ever before, run in rain and low 40°s. So I gambled with my clothes and I think I would've been into hypothermia if the wind had been much stronger and/or the rain much heavier - I've heard that some runners did have to deal with pretty heavy rain. I don't have a lot of choice in shoes because my feet are so wide, so I'm lucky that the pair I'm in now don't take up a lot of water - I've had shoes before that got super heavy when they were wet. Picked my socks carefully for a pair that I thought wouldn't take on too much water, would give me enough cushion for 26.2, wouldn't stretch and bunch, but since I'd never done that distance in the wet, it was an educated guess. It was an ancient pair of SmartWool socks that they haven't made that style for years - hope they keep lasting!
My biggest lesson was in fueling, though. I learned the hard way last year, when I bonked hard, and so I pushed a LOT of Gatorade on the course this year (couldn't get any gel after about halfway because my fingers were so numb, it took me probably 1/4 mile each getting the last two I did take, so I gave up on the rest. I'd completely forgotten the wad of toilet paper I'd stuffed into my belt, which I'm sure made it tighter and harder to get anything out!). It was a revelation to me how much better my BRAIN was working in the last few miles, way better than any goal marathon before, even though it was only last year's Boston that I knew (afterward) I was under-fueled.
If you haven't seen it already, watch the video of Meb crossing the line. Sorry I can't pull up a link easily on mobile. Sad he didn't win, but the guy's a class act.
Speed comes from what you put behind you. - Judi Ketteler