This is exactly where I'm at. T-Mobile is super fast in Oakland, SF, and even in the BART tunnels, but I just went home to WI and had terrible T-Mobile coverage

This is exactly where I'm at. T-Mobile is super fast in Oakland, SF, and even in the BART tunnels, but I just went home to WI and had terrible T-Mobile coverage outside of Milwaukee. So I popped in my Ting SIM (a Sprint MVNO, $6/mo to keep the line open, pay for what you use) and instantly had good coverage.