you pretty much have everything covered, except you will probably want to experiment with the height of your stem, so leave it uncut and use a lot of spacers until you find out where you want to cut your steerer.

If you are doing it for the sole purpose of using threadless stems, I would reconsider since you probably don't have much to gain over just getting a different stem. If you are so dissatisfied with your current trail, then that's up to you to change, but I don't know if it's going to be a worthy investment.

If you want to experiment with a quill-threadless adapter, I've got a couple in my stash. PM me if you are interested and we can work something out.