Camper Ron, you say you are a Sprint cell phone user & wonder about internet access. I, too, use the Sprint service and have found it to be pretty reliable and available most everywhere I've travelled.
So, when they announced the free air card program with unlimited usage for $60/mo, I took it. I should say first that I use the internet for my part time business which I pursue on the road, so the constant search for wifi spots became irksome.
I have had the card, Sierra 580, for only a week, so this is definitely a "preliminary" report, but so far I have to give it high marks for reliability and speed. It's almost like broadband where I am parked, but then, I haven't moved to other locations yet, either.
When you consider the cost of broadband in a home environment (in my case also about $60/mo), and when you consider the initial expense and higher monthly charge for satellite, the Sprint plan is a bargain.....if you need reliable, always-there service. The offer is only good for a few more days I believe.
Just my quick review, FYI. Hope it helps.
PS I considered the cell-phone-as-modem concept for many months, but saw the potential of being hit with a huge overuse bill as a formidable-for-me negative.