What is great about the USB adapter John has given you a link to as well as the Deliberant USB adapter
http://www.deliberant.com/estore/web...or-radios.aspx you can get very creative and attach an outdoor antenna to them. Either a flat panel (Directional)or a Omni directional antenna (360 degree directional). I can personally tell you with a 16dbi flat panel antenna connected to one of these devices you can reach out and shake hands with hot spots over 1/2 mile.
Using a vinyl marine antenna mount you pick up at a boat shop for about $6 you can add a section of PVC for a mast for the antenna of your choice and you mount this to your ladder rack or the roof.
Then use an LMR 400 cable with a male N connector on one end and an RP-SMA connector on the other end to connect to the USB adapter. Or you can order a Male N to RP-SMA adapter and convert a male N to connect the USB adapter. The LMR cable can be ordered any length you need. Run the LMR cable into the RV (Your Choice for entry) and connect the USB adapter to the LMR Cable. At this point you could use an amplified USB cable to run to the computer (17 footer about $15.89). Try USBCable
http://www.usb-cable.com/usb-extension-cables.html
With this setup you can probably get on to the network of a park even if you are out in the back forty. Another good thing about these USB adapters they come with a setup utility that makes it pretty easy to install and to get up and running. You don't need to know a lot about networking and assigning IP addresses etc.
I hope I didn't make this sound all that complicated. It really isn't. These adapters with a removable antenna just allows the use of an array of antennas connected to them.
JB