Liza
10-05-2012

NPC's are levels 25-27, a good place is around Upturned Boulder.

Nina
02-23-2014

R20 search at boulder right after entering entrance:
Fan of sandalwood, Dull scimitar, SWMP, Dull cutlass, Silver-plated armour (I got a collector's edition ... 20/15 dura, 6 att 90 def).

Donce
05-11-2014

Ivory Recorder can be found at Large tree.

Argy
11-12-2016

Collection R13 , Vigour 775, University skills for field activities 1 & 2 engaged.
Collection Points in clockwise,

Large Tree - 85 Silk, 50 Blue Ore, 55 Oil, 30 Logs, 425 Rock
Flower Red - 69 Silk, 105 Blue Ore, 110 Oil, 25 Logs, 390 Rock
Upturned Boulder - 100 Silk, 175 Blue Ore, 165 Oil, 95 Logs, 90 Rock
Upturned Boulder - 20 Silk, 50 Blue Ore, 70 Oil, 20 Logs, 470 Rock

Upturned boulder in the North East looks best for high value items.

This was checked only once. Might do another round of collection to verify if the numbers are more or less similar.