I was out of school 15 years raising kids. I have thousands of hours of volunteering on my application, and a large portion of it is due to my kids: PTA, school committees, coaching little league, fundraising for band, sports teams, and clubs, volunteering at our church, etc. I added some hospice volunteering when I went back to school and did a shadowing program for two summers where I got in 100+ hours. The only thing I couldn't manage to fit in was research, but I chose a mission-based school that didn't care about that.
It's not hard to rack up over 100 hours volunteering in the course of a year...just do a few hours every week, consistently. Choose something where you both volunteer and get patient contact (why I chose hospice), and you kill two birds with one stone. If you need nonclinical volunteering and you have kids, either volunteer with their activities, or find something you can do as a family (animal shelter, providing meals to the homeless shelter, packing boxes at the food bank, etc). If they're too young to participate and still need constant supervision, you'll have to find a way to trade babysitting or have a significant other or family member help out for a while. Also, medical school isn't going anywhere...you can stretch things out another year if necessary to get everything done. Think marathon, not sprint.