The best way in your case would be to rough cut it into oversized pen blanks (to accomodate some warpage) and then dry those, since pen blanks will dry pretty quickly (compared to a large chunk).
Microwaving can work, but it runs a high risk of splitting the wood, and takes a lot of time. I wouldn't recommend it. The alcohol trick involves soaking the blank in denatured alcohol for a while (say overnight), then proceeding to air dry. Despite many vigorous supporters, I haven't seen good evidence that it provides a significant reduction in drying time. It supposedly displaces the water in the wood with alcohol, which then evaporates out more quickly. It might be worth trying if you are in a hurry. For any of these methods, you can monitor your progress by weighing the blank on a postal scale. When the weight stops dropping, it is dry.
Anything involving air drying requires balancing rate of moisture loss against risk of splitting/cracking. For turning blanks, they are often wrapped in green shavings and/or paper bags to control moisture loss. Another method is to coat the end grain (or the whole piece) with Anchorseal or paraffin wax. The more complete the seal, the less it will crack and the longer it will take to dry. What works best depends a lot on your local climate (humidity conditions), the species of wood, desired end use, etc. The rule of thumb is one year per inch of thickness plus one year. With some of these drying methods, you might get that down to several months instead of years. A lot of that depends on how dry you need them to end up before using/selling them.
If you need to go faster than that, you really are getting into kiln territory. That will require at least some investment, which may or may not be worth it to you. There are plans on the web for constructing simple kilns using fabricated enclosures or even old refridgerators. Heat usually comes from light bulbs. Fans and dehumidifiers do the rest with some simple controls to drive it all. That can do the job in several days to several weeks.
