At level 80 with a regular flying mount it is possible to gain 3000 reputation every 15 minutes. Once you reach friendly fly to Sporeggar. Grab the quest [64] Now That We're Still Friends... and fly to the northwestern corner of Zangamarsh. Kill all of the Greater Sporebats, collecting the Fertile Spores. You should be able to gather at least 12 spores for two [64] More Fertile Sporesω τ α turn-ins (750 rep each). Then fly to the islands in the middle of Marshlight Lake (just NE of Sporeggar) and kill the necessary naga for the quest. Turn in that quest (750 rep) and pick it up again. You can also turn in the spores if you like. Fly back to the nagas, complete the quest again, then turn in (750 rep). Pick up the quest again and repeat. Killing the Sporebats gives the nagas time to respawn, and earns a glowcap for each [64] More Fertile Spores turn in, on top of the ones you find.
