Most monsters in WoX do not respawn. However, there are certain locations where monsters can, for farming purposes.
1. Nightshadow. Enter the town at night, and the female vampires respawn (low XP per kill though)
2. Castle Xeen. Do not destroy the guard making machine and the Xeen guards will keep appearing every time you ascend or descend the stairs. Use the side towers to farm xp.
3. Sky Bandits (3x cloud dragons). Though the positions where they appear are fixed, the probability of them appearing is random.
4. Sandro if you do not get his heart from the sewers. +100 gems too.
I'm not sure if the monsters in Asp regenerates if you do not destroy the machine, the same for Lord Xeens in Dungeon of Death. I'm also not sure if you can keep ringing the gong in Darkstone Tower to generate Onyx Golems. Those are tough though.
Instead of using the bank/inheritance technique, I am grinding out gold in another fashion, which takes less game time, but a lot more of player's time. I use Sandro to make gems (by this time, I can easily kill him before he attacks me), and then mine out the Gemstone Mines (rolling only for gemstones, reload if gems are obtaineed). I roll for Plate Armour/Mail (for higher profits) at the smiths and then sell. Rinse and repeat. This way, in less than 2 game years, I can get enough gold to train to 200. The XP from killing Sandro is also useful in having the required XP for training. Use the remaining level raising items/awards (Clouds + Darkside, all untouched to date) to reach 255.
It's boring, but you can simply use your current characters for it. I inter-spaced these gold grinding operations b/w stages of Darkside, once I have the ability to safely grind gems from Sandro. This helps preventing it from becoming too boring.
All you need is to have 250k gold for the initial Gemstone Mine replenishment, Sandro's quest uncompleted (and not having his heart in your quest inventory!), sufficient stats to kill him before he attacks (you can use the Day of XXX spells at 5AM to maximize efficiency. You can even cheese it with the Xeen Slayer Sword, which bypass all physical attack resistance). Needless to say, you will have the Merchant's skill a long time ago for everyone in the party.