Get Consumer Cellular and don't look back. It is geared toward us older folks and use both AT&T and Verizon towers.
I don't have Consumer Cellular so not trying to "sell" you. I've had at&t since before it was at&t.
Vihtavuori N110 is all I use for 357mag. It has a lot broader load range than H110 and isn't as volatile at lower loads. 14.3gr is a good mid range load. I recently loaded 500 for my dad at that load. Very clean burning even at lower loads.