I've tried doing this with SuiteScript 2.0, but did not have the same success. I know this is an old conversation, but has anyone had any more luck with updating the item options field? Is there another way to accomplish this?

That sounds like an interesting solution. We do have a storage and expiration mechanism for access tokens that we created for a different service we could probably use. How exactly is the folder linked to your particular record? Is it by name?