What about the bearings in the spindles, etc? They look like miniature skateboard bearings and i know just a little bit of water can really affect them.
Definitely a valid concern. If you have rubber or teflon sealed bearings, you might be okay, but anything else will get contaminated with water. You can take care of that by flushing them with WD40, but that also washes all the rest of the lubricants out of the bearings as well.
Something that I used to do when running in wet conditions was to install an old set of bearings or bushings that I didn't care about.