You can add your own ACF fields to properties and keep their values across syncs.
- Create an ACF field group.
- Set its location rule to Post Type = Property.
The field group appears on the property edit screen. Your custom values are preserved across syncs because the sync only writes HomeRunner’s own fields.
Field names to avoid. Do not use field names that HomeRunner already uses, such as minimum_stay, photos, internal_name, or currency. Those fields are overwritten on every sync.
What you cannot customize this way. The property title, description, and excerpt are refreshed from your PMS on every sync, so you cannot customize them with ACF fields.