Recipe(tried): Crystalized ginger - additional info

I cut off a couple of additional suggestions.

While the ginger is cooking in the syrup you can add a few strips of orange peel or lemon peel which will add a slight citrus flavor to the ginger and the syrup.
You can also use grapefruit but never use lime peel - lime peel turns gray in heat and will discolor anything else in the syrup.

During kumquat season I toss in a few of the whole fruits which I have pierced all over with a needle. After finishing the ginger I continue to simmer the kumquats, alternating with periods of cooling, for a total of about 36 hours, to make glac fruits with a ginger flavor.
You have to alternate the heating and cooling to allow the syrup to percolate into the fruit. The heat drives internal moisture out and on cooling the fruit absorbs the syrup.