The only realistic way of making that much money in such a short time is to play the MB.
You can make good money through gathering - but only by gathering stuff that sells well on the market and then selling it. Requires you to know what items to gather and what price to ask etc. - i.e. knowing the market.
Same with crafting - you can make money that way, but it requires knowing the market - and the market will not only vary between servers, but also change over time.