Iris refuge needs a little help: sensor suggestions, “away” rules for thermostat, Sonos Integration?

This can be done with an app that handles the work. I don’t use such an app but I know there are both free and paid apps that will do this.

Personally, I set up Location Modes for Home, Away and Vacation. Then, I use webCoRE to set up daily schedule to run only when we’re home (i.e., Home Mode). I then set up webCoRE to monitor our distance from home (iPhone presence). When we’re either in ‘Away Mode’ or ‘Vacation Mode’, the daily ‘piston’ (i.e., program) no longer runs it’s daily schedule. Further, the heat and cooling setpoints are changed accordingly. and lastly, depending on the season, the Away and Vacation thresholds ‘rings’ are also adjusted to allow sufficient time to make the house comfortable again.

You may or may not not be ready to tackle webCoRE yet, but when you are, take a look here.