Access to headless raspberry pi?

Question

SSH

How would you ensure guaranteed access to raspberry without a monitor and ethernet?
With wifi, I see the problem in that the interface may not start the access point for thousands of different reasons: power is lost and the raspberry will hang on fsck, another USB device is connected and the interface address has changed, etc...

Answer 1

3G whistle as WiFi backup?
no dependency due to fsck. if the file system is dead - that's it, hello to the family.
By the way, the raspberry has a built-in watchdog, it's worth setting it up. Saves from service freezes.