Want Verizon and ATT SIMs in West Coast USA

I travel up and down the west coast of the USA, often camping. In the past, I’ve used my cellphone (ATT) and MiFi 7730 hotspot (Verizon) to stay connected. But I was paying $130/month on ATT and so recently moved to Ting (which is great! about $30/month, but is now on Verizon with the V1 SIM). But just last week I was at a campsite where Verizon, Tmo and Sprint had about -120 dB signal, but one of the guests was getting 1-2 bars on ATT. I had nothing that could pull ATT signal, so I was hosed.

Here’s what I want:

  • peplink mobile router that has 2 SIM slots (not simultaneous, it’s fine to switch)
  • advice on which data plans to get: based on experiences, I know that I need ATT and Verizon. I already have a $15/GB plan on Verizon which is OK. What is a simlar ATT plan?
  • Most of the time I am not travelling, so 8 months of the year, I don’t use this device at all, so generaly I’d rather pay per GB rather than per month.
  • [edit to add] Small and low power usage is good, as this runs off solar/house battery.

We offer some paypergb plans as well as sell peplink routers since we are a partner.
PM me for details.