What is the most reliable way to sell a timeshare in NH quickly?

The deeded perpetual time share is in North Conway, New Hampshire, at the height of fall foliage season, Columbus Day week in October. The Resort will not help us to sell it as a resale, so we will need a reliable firm to do it for us. We do not want to be waiting for years. We hate to give it up, but we just cannot get up there every year as we once did.