Just back from a 2 week RV Trip through the Southeast and I thought I would update on my experience with Walmart's "Internet-On-The-Go".
I bought the device early in the morning on 9/12 and plugged it in to charge it, once I got home. At that same time I went online to their website to activate it. Later in the afternoon, I figured it was fully charged and tested it, the 3GB I bought was applied and I was able to get the internet. We left home (Southeast Florida), on 9/13 and traveled up Florida via the Turnpike, then I-75, up through GA and Atlanta, then into the mountains NE of Atlanta, then into NC up toward Asheville, then Chimney Rock, then over to Asheboro, then further east to Warsaw, NC. After that we headed home, back towards Fayetteville, NC, then down I-95 to South Florida.
We were able to get internet almost every time we tried while on the interstate highways. We were not able to get it at the campground we stayed at outside of Blairsville, GA and also at the campground we stayed at just east of Chimney Rock, NC. We were able to get it at all other stops.
We used it as much as we wanted and needed to. For the whole trip we used about .4GB of data, less than half a gigabyte. So it seems this device and plan is a good fit for our needs. We will be home for a couple weeks, then we are taking a long weekend trip to Tampa, (in the car, not the RV), and we will probably take it on the road with us. After that, we are camping in the RV for a weekend in early Nov, and will take it again. Most likely, after those trips, we will still have between 1.5GB and 2GB left.
As far as the refills, we signed up for Auto-Refill, so I can't report on how well that works. But since the initial activation/being able to actually use it, went pretty smooth, I imagine the Auto-Refill will go just as smoothly.