I would recommend completing the side quests in your log before moving on to Mooshu. That way you can have a fresh start in Mooshu and not have to go back if you don't want to.
I just got to Mooshu but I still have like 7 side quests for Marleybone. Should I continue in Mooshu or go back and do the other quests?
I agree with Professor Greyrose, but for different reasons: you side quests will most likely boost your level by at least one. You will also gain experience battling different mobs. Mooshu is my favorite world, but parts can be fairly difficult if you get there at a lower level.
I would recommend completing the side quests in your log before moving on to Mooshu. That way you can have a fresh start in Mooshu and not have to go back if you don't want to.
Such good advice Professor Greyrose. I wish all Wizard 101 students would follow it. Doing ALL quests is the best way to level up and be prepared for what lies ahead.
Depends on what level your wizard is. 25-30 = Do all of them so Mooshu doesn't take forever to do. 30-35 = Do 3 or 4 side quests, then go on to MS. 35-40 = You're good to go, Mooshu won't be hard for you.
On my first wizard ever, I didn't do side quests OR Grizzleheim, so Mooshu was a pain in the ol' tushy for me. Good luck!