I've been keeping track of our internet usage as we travel, and after 7 months (April through October) of traveling in 9 state (WI, MI, IL, IN, IA, KS, CO, NM, AZ), here are the results:
Total campground visited = 43 (15 were state or county).
Campgrounds with WiFi service = 7
Average Data Download (Campground) = 2.1 Mbps
Average Data Upload (Campground) = 1.0 Mbps
Average Data Download Speed (Verizon UML290 in Cradlepoint MBR95) = 8.1 Mbps
Average Data Upload Speed (Verizon UML290 in Cradlepoint MBR95) = 1.6 Mbps
Average Data Download Speed (Millenicom MiFi w/Sleek + roof antenna) = 5.2 Mbps
Average Data Upload Speed (Millenicom MiFi w/Sleek + roof antenna) = 1.0 Mbps
We have a 18 GB/month Verizon Share Everything Plan + Millenicom's 20 GB/month plan. Data is shared between 2 laptops, 1 tower PC, 2 iPads, and 2 iPhones.
We averaged 1.01 GB/day of data usage over 7 months.
Most data used per day was 5.1 GB for an iTunes movie download (Never, never again!) which forced me to up our 12 GB/month Share Everything Plan to 18 GB.