Now that the forum is up I thought I'd throw this out as earliest as possible for the event attendees.
If you prefer not to take advantage of the free onsite camping area, where there are also showers and restrooms, there are numerous options in the surrounding area for lodging. September is a very busy time in the Sierra Nevada Mountain region and lodging availability can become tight. Several options are available, like "Glamping Tents", but limited, through Bear Valley Ski Resort, by calling 209-753-2327, x100. Or you can find other area options by visiting https://www.gocalaveras.com/. In addition, please refer to third party booking sites such as https://www.airbnb.com/ and https://www.vrbo.com/. Please feel free to share what you find out there to hopefully help out others too.