Unfortunately, my community no longer has much activity and the cost is not something our club can continue to afford.

What is the best way for me to archive the forum (database, contents) so that at some point in the future we could potentially spin up a new license / copy and restore it?

Related - I cannot see how I cancel my license renewal in the client area. Do I just take the forum offline?

Please submit a contact request to our accounts department for assistance with cancelling your license: https://invisioncommunity.com/contact-us

As you’re self hosted, you would just take a backup of the files and database and that will be what you restore should you wish to resume your community. Once you get the backup, you can decommission your hosting. 

Thanks Jim!