As for Tasker on an Android phone, there is also the ‘WiFi Near’ state that might be an option if your smartphone is connected to any other wireless network in your community.
Nowadays, there is also the ability to use Tasker HTTP Request with the SmartThings API to toggle device(s). As for presence, I have Tasker toggle On/Off a virtual presence device via the SmartThings API when I’m outside a larger geolocation area than the area I have setup in SmartThings. I call it my ‘Traveling Mode’ presence device since I’m outside my hometown area. And as a backup to the sometimes flaky SmartThings geolocation feature, I also use Tasker to toggle off my virtual home security switch via the SmartThings API.