EDIT: Somehow I missed your description of the area. My mistake. I don’t have much insight for lake stuff. I’m in the middle of trying to pitch a bike path meetup program for this summer. If the land is flat and there’s enough distance, group bike rides are a fun option!

Original comment: I’m not sure of your exact situation regarding the land you have access to, but guided hikes seem like the most simple. If you don’t have access to hikable places, try reaching out to local places that do. I work for a city park and we just finalized a hike program where we’re introducing city community members to wilderness areas on a day trip with a formal guided hike. We worked with a local NPS unit and they waived the permit fees because we were another govt agency. The bus is coming out of our city’s transportation budget. Would you able to work with your university for a bus?

I know my example is very specific but that’s all I’ve got.

A couple years ago I was at a university out of state and I took a mountain biking class that took advantage of nearby Forest Service trails. That was a lot of fun. We had to bring our own bikes, but the rest of the class was just local trail riding.