Welcome Hordur,
Looking forward to seeing your first project, and you getting you're workspace setup can take it's time but in the end it's worth it, i'm an infusion only workshop.
Tailbox for the bike sounds like a decent first project depending on size, but do lot's of smaller tests and have fun

I'm only really starting out with the CAD/CAM stuff, I have access to a home built mini mill and have been experimenting with milling moulds directly, this might be up your street.