Depends on PvP or PvE.
-If PvE, or very light PvP, I recomend the plateau at 52. 48, as it is centrally located at is closely located to metal, crystal, beaver dams, but it would be difficult to defend.
-For PvP the small cave at 50, 29 is hidden and can be easily defended. You may also want to consider the base of the wrecked obilisk in the desert, it is a sort of caldera ans hidden by the obi. (20,70 ish?)