Use morgul decay, and your most powerful attacks. If you have Elegost, have a grace of Athelas, and have Idrial's gift of grey haven when your hp is really low. If you don't have morgul decays, you'll get killed really easily, so travel back and find some.
well thats not completly true.
i did it without a morgal decay i just have a leadership skill on berathor that regains my ap so idrial can use gift of grey haven