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.
Use the resource appropriately and fairly; heavy socket use like streaming netflix or uploading YT vids can seriously impact the shared network. If it's a business, spend your money there. Follow the guidelines in the End User Agreement on the splash page.
In order from simplest/cheapest to most complex/$$$
relocate the device or park the vehicle so the laptop has a clear[er] view of the target. Line-of-sight through glass is better than having metal in between.
External adapters are a single-device solution; they get wifi into that device.
Dongles (and routers – see below) with removable antennas are nice because you can upgrade to an antenna better suited to your uses. Commmon upgrades include:
Wifi extenders/repeaters/routers work by hopping a wifi signal from some further access point. They are multiple-device solutions; all your devices will leverage the repeated wifi.
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).
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.