Mistmore doesn't have the mob density in my opinion compared to other options, plus awful pathing and running mobs. Things peolpe don't know either for 18-30, Dalnir is epic. Respawns zone wide are 7 minutes

(Oh, and also it has a pretty good ZIM)
In kunark I was able to pull the entire top floor every 7 minutes to level 24, then drop to the bottom floor and train the enitre zone to the one way wall, then pull the other side of it.
I normally head to guk as other suggested at around 28 to finish off the grind to 40.
My leveling takes about 1 hour to get to Unrest + level to 18ish.
A little over an hour and a half (maybe 2 hours) to get to Dalnir + level to 28.
Then like 2ish hours or so in Lguk depending on if I can pull the entire zone.
If you're not pulling zones of mobs (or unable to), then other areas might be better.