The greater vault is usually harder than the ToEF. I recommend doing the water temple, darkforge, the high kings, and then the ToEF, followed by a dive to the casino, as well as grabbing the cats eye ring in case you still qualify. Afterwards you will have the oomph to take on the vault.
For the ToEF all you really need imo is a blessed potion of cure corruption to throw at the wyrm and a fireproof blanket or (hopefully) more than one. If you bless (and rustproof) the sword it will resist item destruction quite well, even in the toef.
Last edited by grobblewobble; 12-26-2018 at 12:40 PM.
You steal a scroll labelled HITME. The orc hits you.