Other mages may be able to help more than me. XD Personally, anything where you don't get hit a whole lot (since mana shield uses your mana, and you don't have a whole lot of health).
East caves should be no problem, in the hollow tree Vilefang and Cladt should be doable if you can kill them quick enough. Noxxara will be tough, because she hits for 40s.
With a strong mana potion and harvest mana, you may get quite far - it's worth a try. XD
Other than that, play together. Bosses drop more items if fought in a group, give more experience, and you don't die that easily if you're in a team.