I've watched several tutorials on washing bikes, and the general gist seems to be to use a degreaser on the drivetrain, then wash the rest with soapy water, and don't spray hard when rinsing so water doesn't go into the bearings. My question is are there are any special considerations when washing an older bike—in particular about rust?
It's also worth noting that my seat post has grooves cut out to reduce the weight, so water could potentially go inside the seat tube. Should I take care to avoid this, or is it a nonissue?
The bike in question is a 1984 Trek 460, with a CrMo steel frame.