What exactly would I be responsible for if I wanted to lead on one of these dates?
Pretty easy really. Show up with a route (maps &/or cues)& a sign in sheet and you're good to go. The ride leader gets to choose the route so pick your favorite location & roads. You also get to decide start time so sleep in or not - your choice. Also, make sure everyone gets back in.
The club provides the sign in sheet & can help with routes if you want.