I keep a couple of pairs of shoes at work, in case I forget to bring a pair (or in case I don't have room) when I bike. I carry everything in a backpack (clothes go in a plastic grocery bag so my sweaty back doesn't get them wet). I tried the medium sized Timbuk2, but it just didn't hold everything as well as my backpack does.

I can't help you with the coffee part - I buy coffee at work.

Do you have a place to shower (and a locker to keep your shower stuff)? That makes things infinitely easier... if not, I know there are other women on here who keep baby wipes at their desks, etc.

Good luck figuring out the details! It's completely worth it!