1. You can only have a crafting level up to ten times your character's level. So a level 5 character (about the lowest I can foresee gaining a craft, more likely 7 or 8) would only be able to get to crafting level 50. (60 at level 6, etc.. up to the maximum crafting level of 400 at the current maximum character level of 40.)
2. Mining and Herbalism harvest points are plentiful, but somewhat spaced out. Still, it really only amounts to pressing Z every so often as you wander the lands doing quests. Disassemblers, on the other hand... *sigh* They have to buy the materials they disassemble (or they can chop up chest and quest rewards, but that's... typically more costly.) and have very limited options as to what they can chop up, so they have a very hard time of it. Crafters get their supplies from Suppliers, and a "key ingredient" from their Craft's Trainer, so it's either the Auction House or mail from an alternate/guildmate/friend and a visit to their trainer in their faction's main city to get what they need.
3. They level extremely quickly. Unless they accelerated it for Closed Beta, it never takes more than five successful craftings or harvestings to gain a skill level in that profession.