Unfortunately, if you really want to craft at 50+ level, you really must take all crafts up to 50 in order to get the cross skills.

The best way is to run the crafting log to 10-15 or so, then do GC turn ins and leves. Also, I advise leveling gathering at the same time. If you progress all of these at the same time, they are very symbiotic - mats you need for crafting can be obtained by the gatherer at a similar level. Crafted mats needed for one crafts recipe can be made by other crafts at a similar level also.

Its a long haul.