Working in a library becomes language arts or computer science. Guiding tours in a museum can science or history. We called it electronics and science. Integrating volunteerism into curriculum make be looking at things backwards. You have to check with the eventual degree-granting college or university ahead of time.
All colleges have different standards for what counts.
They complete applicable forms, cross their fingers, and wait. All homeschoolers should ask for financial aid forms at the same time that they request college application forms. Then they need to submit everything at the earliest possible date.