I use a Dell Rugged Tablet running Ubuntu Linux with a combination of programs. My Rugged Tablet has a built-in 4G broadband card and a built-in GPS receiver. I use a 4G and GPS antenna on top of the Jeep for the best signals. My favorite program is OkMap. It's a Windows program that has way too many features to count. Unfortunately, it's not available on Linux so I need to use an emulator. This setup allows me to store an entire base map (approximately 44 gigabytes) on my local machine and have unlimited offline maps. I have the entire state of Arizona with over 2 million map tiles on my machine.
To create maps, tracks, and points, I use a GIS program called QGIS. It's an open-source program that allows you to interact, visualize, evaluate, and create GIS data.