Mobile Router that will auto connect to Wi FI- RESOLVED

I used to have a WiFi Ranger that was comprised of a router with custom software and a Ubiquiti Bullet amplified antenna - it was supposed to do exactly what you're looking for though I found it a bit flakey. The router croaked so I replaced it with a regular router / AP. Connected through the AP, it's possible to login to the Bullet. It has several screens that tell you about the quality of signals available. Easy to login from there. Manual connection, but easy and robust. I don't have / need a phone hotspot.