Ben,
I looked into this a bit further and noticed that you might be referring to Location tracking. Location tracking is not available through the API, which means that Method or any other third party application can't access this information from Quickbooks Online. This is a limitation of the API and we don't have a timetable for when this may be available for developers to integrate with, unfortunately.
I would also like to be clear that a custom field created in Method, even if it matches a field in QBO, will still not sync over. Again this is due to the API and also goes for custom fields in QBO, as they will not sync over to Method.
Hope this helps.
- Adam