This idea is for a new “Planned Run” where you’d set date (or day of week if recurring) and time … whether or not it’s recurring … whether or not it can be displayed publicly in a City page … ability to set some notes like parking suggestions, expected distance or time … and maybe some other options.
Each User card can have an “invite to run” option in the three-vertical-dot menu that lets you invite the person to one of your Planned Runs. This might need some form of response/communication beyond accept/deny based on the scheduling aspect.
Each City page could include a new tab that displays any publicly-viewable Planned Runs associated with that City.
This could pair up with Routes, where you can attach a Route to a Planned Run in order to show where you’ll be going ahead of time. For recurring Planned Runs, you might be able to attach/detach Routes.
Although it may be heavy-handed to include a Route - this might be something that the people going on the run will want to collaboratively create. 
Which sounds like a new Route Builder feature what have I done. 
There would need to be several scheduling options
- One-off
- single date and time
- Recurring
- frequency
- this can get complicated, so maybe just limit it to the basic weekly/monthly/yearly as opposed to getting into e.g. every third Tuesday
- day of week
- time
- frequency
It would probably be nice to have a view of the Planned Run that might look a bit like the Challenge page… List all the people who joined/accepted, including stats on how many streets each person completed on the Planned Run.
This would be different from Club / Crew / Group / Team because it wouldn’t require joining anything beforehand. It could also pair with that by allowing Crews to create/manage Planned Runs.