Sleeping right after, you don't want to do you work out and then carry out 8 hours of work on your feet, you'll get much better results doing your work, going to the gym then going to bed.

If I where you I'd encorparate the bag into a few of my 'on' days aswell as my off days You can really push yourself on a bag. Good for keeping you loose, working your technique and keeping your chest loose but equally as good for an intense all over work out.