Rue I'm a DC, same amount of units you're describing.
For me, the most challenging bit is that the job is basically like a line manager role......of volunteers who don't especially want to be line managed!
I enjoy the support of new leaders and struggling units, don't enjoy the email chasing, and organising of events that no one really wants to help organise.
Time wise, it's around 2 hours a week on average admin, and maybe 2-3 hours a month meeting people, visiting units, meetings.