Botany leveling troubles

I'll try my hand at this. After reading/researching for guides and locations, how does one find new leveling nodes? I've been having troubles since level 36 with the lack of available nodes. Now that I'm 43, I've exhausted my Leve's and my log is telling me to go to either Bronze Lake or Whitebrim. Only those two locations. Do I now mine 3 full levels of 6 different items? I did 41-42 on Tarantulas alone, who needs 750?

I did find a site that was nice enough to show you on a map where level 40/45 nodes are, but every time I head to that area, there are none. Anyone else having this problem? I've seen plenty of 50 BTN. Did they just suck it up?