I've ended up with the conclusion that large mistlands base is optional at best; what's more efficient is a small farming/hunting outpost. Couple of things making a location for such a base worthy:
- persistent spawns of seekers, gjalls and rabbits around. You need all of the above for the top tier food and potions, when they come to you themselves is like a "passive income"
- a bit of flat land that can be cultivated to grow mushrooms
- two or three Yggdrasil roots nearby to drain sap
- an infested mine nearby to farm Royal Jelly (when latest announced patch lands, it will regenerate over time in mines)
- near the water to ease transportation of metals

Ideally the location would also be a clear spot never or just rarely engulfed by mist. On my server I found several large valleys where I don't need wisps at all.