Yes, it's a major pain to level to 300, I think I actually did some Dark Iron stuff, with BC now it's probably not that hard to get the mats, as long as you have someone to run with you to the Dark Anvil/Forge (unless you don't need it anymore, I'm not sure). But once you get to 300, it's easy to get to around 350 with the trainer, vendor and early rep recipes using mostly fel iron. As soon as you get recipes for the weightstones, sharpening stones, and runes of warding/shielding, make those - they only level you up for about 10 levels, but they're the most efficient for mats.
After that, I'd go and farm recipes in the OL instances. Felsteel can make some money, although you'd probably make more just selling the ore needed to make all that felsteel: e.g. Felsteel Helm = 8x Felsteel Bar = 24x Fel Iron Bar + 16 Eternium Bar = 48 Fel Iron Ore + 32 Eternium Ore. Felsteel Helm sells for about 55g on my server, I'm sure I could get more than that selling the ore, but it wouldn't level my BS.
Also, the Aldor/Scryer recipes aren't too bad to make, they sell alright as well.
I'm at 367 now, I just gather as I see it (saving up for my epic flyer) and when I have enough, I make felsteel stuff to level. I farmed the Khorium set of plans for myself, but I have a feeling Felsteel is the easiest set to get the recipes for, just run those instances (Crypts, Arc, and SL) over and over, you'll get more of worth than farming the Ragesteel and Khorium - although I did get to Revered with Kurenai from farming Khorium, as well as getting a good amount of Aldor rep tokens.
I still think it's worth it to slowly get up to 375, just to be ready for WotLK. Having said that, will there be anything of use to us in that expansion? We can only hope - as an armorsmith and paladin, it's a gamble.