It's worth visiting the bank when you have a lot of gold to spare to get some interest.
To be honest, as soon as I left Vertigo I went to a weird pyramid that took me to darkside of Xeen, I ended up going to a town and ridding it of gremlins, and eliminating the rats in the sewers, and doing two of the three chest puzzles and then I ended up doing various quests on both worlds. Killing The Count in Nightshade? (Can't remember the name of that town) getting the Alacorn horn from the witches' tower, among a few other quests, I even found quite a few quest items for quests I haven't even gotten yet. I have tons of expensive weapons and armour and am rolling in exp and dough :D and I never did find the Dwarf Mine ;)
Though while I have about 120,000 gold, I'm still not investing in buying the run down castle for 50,000 until I have way more.
But yeah, I'm totally enjoying this :D