For exp hunting locations, I have quite liked the planes.
- Plane of Nightmare
- Plane of Innovation
- Bastion of Thunder
They are quick to get to.
If wish to take a break, but not offline, zone out to PoT, afk and save the buff timer decay
Short run to PoK for spells / vendor if needed as go up levels later 40s to early 60s.
Bonus as well for PoI
(level 55) and BoT
(65?) as they do appear in Franklin daily quest rotation.
Typical, kill 5 of X and get some exp and a tradable 'intricate defiant' item, shoulders, back or belt. Depending how you are gearing up, this could be the first haste item for belt. This is a pick-up only task from Franklin, and you are rewarded immediately on the task completion
(e.g. 5th kill).
Veksar is nice and I have whack-a-mob hunted there.
Against it, is a few zones to cross to get there plus the water swim to zone in, then getting to the deeper camps in zone takes time.
For it, a zone that offers a steady increase in mob levels that cover the high 40s to 60s range.
It can also appear in the Franklin daily rotation, although the times I've seen it come up its for the highest level frogs in the north east corner of the city maze.
If the group has gains to be made from dps vs undead, they are in this zone as well.
Either can cover the the late 40s to 60s range.
But always be strong enough to handle 2 or 3 mobs concurrently, better with a CC to help lock down.
Better to have a bit weaker mobs, a bit less exp coming in, than trying to go too high and suffer wipes, recovery, loss of buffs etc.
EDIT: for anyone not knowing of Franklin in PoK.
Franklin NPC details
Daily quests, for level 20 upwards, at staging of 5 levels.