A few thousand gold and the AH is all you really need to level up JC. Follow one of the online guides and buy your mats as needed and you can level this by hand in an hour. Also, a lot of the crap you make can actually be Disenchanted if you have an enchanter toon so you get back some of your costs that way. If you want to farm mats on your miner just use some of the various different zone profiles on the site (old world, Outlands, Northrend, Cata Zones) and then send the gems you get to your JC for crafting and the Ore you get for prospecting. I still find it easier to just buy your mats, costs a bit but easier than doing all that farming is so many different zones. the only annoying thing about JC is that you have to do all those annoying daily quests to get all the patterns you want. Aside from that, leveling it is very easy.