Off the beaten path?

[Swish]

Kedge Keep is good from the early 30s up to 50 if you've got some enduring breath on the go.

South Karana is less populated, 20ish - 35, and into Splitpaw.

Spectres in OOT will probably be quiet from 38-45, as most people will tend to go to the Oasis or Feerott ones.

Never done much in Permafrost, sounds like a good time.