Where to map freeform data?

I am new to HL7 and FHIR and have an application that manages patient engagement particularly for the homecare setting but also used in surgical situations.

Within the app we have a section called a care journal. It includes care journal entries ordered by creation date. Each entry is a rich text field where the homecare practitioner (or other authorized user) can record things like what was done during the visit, the state of the patient, activities, photos, videos, or really anything of value to the continuation of care. There are other sections of the app, albums (categorized by users) and posts (date/time ordered), with similar free form data where practitioners, family members, the patient, or any member of the circle can contribute, comment, react to content.

The circle is the term used in the app to represent the collection of users with access to some (public to all members of the circle - posts and albums) or all (public + protected / permissioned area - care journal) of the care recipients information.

Mapping the organization, patient, family members, care providers, etc. is fairly straight forward and the resources are well documented. Mapping events, surveys and responses also relatively straight forward using the appointment, questionnaire, and questionnaire response resources. Where I could use some guidance is how to map the free form data and media to one or more resources that makes sense for other systems to consume.

I’ve looked through encounter, observation, media, document reference, document manifest, etc. and none seem quite right. I suspect a combination of encounter and may be okay but for some entries may be overkill.

The fact that any user with permissions can create a care journal entry, post or album entry makes it tricky.

In the surgical care world, the care journal could contain pain scores, wound photos, care instructions, etc. while in homecare it could be task completion notes, exercise, food intake, etc… Albums and posts are more likely to be activities, reminders, information about the patient or their family/likes/dislikes/etc., information about the surgery/process/clinic/rehabilitation/etc.

Thanks in advance for any pointers. Please ask for elaboration if I haven’t been clear in my question or scenario.

The community seems to have landed on DocumentReference as the primary mechanism for capturing ‘notes’. In R5, it’s also supplanting Media.