The internet is a lifeline for 'dwellers but it not always available in the ways it is for sedentary folk. There are several challenges:
Wifi is to internet access as shore power is to electricity; cheap and plentiful. When wifi is available one should be prepared to take advantage of it.
Wifi extenders/repeaters/routers work by hopping a wifi signal from some further access point.
Many also remember SSIDs (access point names) and will reconnect to them as you travel. You might pull into a McDonald's parking lot and hear your phone ding: the router has already connected to the wifi and your phone 3) is asking you to click to agree to the wifi conditions.
High-end repeaters/extenders like Ubiquiti typically mount outside the vehicle. This makes for maximum range but can reduce stealth. Antenna wire losses are eliminated because the antenna is inside the receiver, and the signal brought into the vehicle over ethernet4).
The Alfa AWUSO36-series is famous for range and technical abilities. Having a separate USB may allow you to put the wifi receiver in a window/dash and keep the laptop inside.
Mobile (or “cell” data) is the internet access provided by mobile telecomm networks:
Perhaps counterintuitively, having a non-Verizon carrier can actually be desirable at RV meetups, since everyone else is likely to be hammering the Verizon towers.
Often you can buy data at cheaper rates. Mobile Virtual Network Operators (MVNO) are resellers who buy excess capacity from major networks and sell it to customers at reduced prices. Examples: Boost (Sprint network), U.S. Mobile (Verizon network) and many others.
The tradeoff is that your data may be deprioritized when a particular tower gets congested. Your data will still work, it'll just be slower when all those folks paying full retail start streaming Netflix at 7pm or whatever. Can't put up with that? Pay full price and take your chances with congestion anyhow.
If you want to find an MVNO for your preferred network, search for “verizon mvno”, “T-mobile mvno”, etc.