For fishing I usually go to Yojamba island. Can be a pain if you're getting griefed by bored lvl 60's. The trick is just to find an uncontested spot where you don't aggro any mobs.
For furbolg you need to get help from other lvl 60's. You move your twink to one of the Furbolg villages in Felwood, die on your twink, then spirit run to your corpse and stay in ghost form, while people in your group (not raid, you will get less rep this way) kill the Furbolgs. If you don't know anyone who can help you, you could try and just move your twink there and try and contact the people questing/grinding rep there if you can join their group for some free rep. Or offer to pay them I guess.
Furbolg 2
Explore southern and northern Felwood at an early level, then the x2 places in Winterspring where the Furbolgs, west and east of Everlook. Then you can go there at anytime and just stay there as a ghost spirit when people are farming it for you.
Exploring places like STV, the road to Winterspring etc is not required, but it's smarter to manage your exp as low as possible at lvl 19