Weekly and the various starting quests for F2P are the key reputation options BUT as DF reputation is acclimate, you can make goofy alts to help regrind or gain the reputation for your main or account.
There is no easy profession besides skinning which is auto learned via skinning any mob in DF or in Darkmoon Faire wolves or Northend sharks. There are not many Artisan's Consortium quests for F2P.
The easiest DF reputations are the ones you can turn in totems or others items for reputation as those can drop from chests and disturbed dirt. But so far I have not found items like that for the Artisan's Consortium besides crafting.
Side Note -- If VET, with sub you can do the Crafting Orders on the same account for Artisan's Consortium even @ <= 20. If Linked Vet with higher toon that unlocked DF endgame you can have more options.