I would wear capris, but I get cold easily and don't like feeling cold. I don't know what that would do for chafing. Make sure you bathe in body glide before the race though.
A high of 48? How cold is it going to be at start time? Definitely a visor....then I might do capris w/a tank & toss shirt....But I could do shorts. This is hard weather. I might do a long sleeve, but make sure it's really fitted. Anything loose & waterlogged would annoy me.
I'd probably do either compression shorts or crops, just something tight-fitting, and a tank top. Unless it's going to be really chilly for most of the race, and then a tight-fitting long sleeve. I prefer a visor to a hat.