Between levels 20 and 24 I soloed aviak guards in Lake Rathe. There is one
spot just outside the Arena zone (after turning right from SK zone) with two
spawns far enough away from each other that you can drag one without the
other noticing. Further down there are two spawns right next to each other,
so you need someone else to take the other one.

Lake Rathe seems to be a soloists zone, with people rotating the spawns
rather than grouping. I have no idea why, but it suits your purpose. The
loot is reasonable, pretty good cash and the odd bronze weapon. For me, a
simple melee/smite routine worked fine.

If you get one spawn to yourself, you should have enough time to be able to
hop around from foot to foot with full HP and mana for just a little while
before the next spawn.

Salt