Mistmoore Castle is a good soloing location, at least during the hours when it isn't absolutely packed. Ideal for a ranger since it's outdoors, allowing you to harmony around from camp to camp. There are only a few pieces that are suitable for rangers, but they are upgrades from banded. Crested spaulders/helm, hooded black cloak, and diamondine earrings. Additionally, there's a decent chance of getting the needed drops to complete
one part of the
Call of Flame quest, for the level 49 ranger spell.
Also, a few zones over in Steamfont, you can check track for the Minotaur Hero. Kill and loot the needed shackles. Bank until you're in the Qeynos area for the turn-in to receive hero bracers.