How to maintain the bicycle after a commute, when not home?
Do nothing.

Yes, nothing. Unless you are biking wearing a hazmat suit through some corrosive volcanic crater where it rains acid.

Rinse it off, at home when it's convenient, or it is especially dirty. Give a more thorough cleaning once a year in the spring. Lube the chain occasionally when it begins to make some noise. Other than that, you really don't need to screw around hosing your bike off so much. Just ride, it'll be fine.