I ran a laptop, mounted to a Ram mount for off-road GPS. Found those little screens too hard to read.
The laptop runs Garmin nRoute (discontinued, but still available for free online), it ran all the Garmins maps I had for use with Garmin mapsource. I could download tracks and routes I made sitting in my recliner, or routes you can find online at places like Traildamage.com. You can also transfer routes and tracks from Garmin nRoute to the Garmin mapsource programs.
Since laptops usually don't have GPS built in, you need some type of GPS receiver or antenna to attach. With Garmin software you used a receiver that magnetically mounts to the roof, and some free software to run the receiver signals to the nRoute software. I will say it worked great, and the reason I went with nRoute was I already had almost all the Garmin maps and was familiar with the software.
If all new, then look at Delorme that also has software that can be used in the similar way...I believe that's what Hunner used on his laptop setup.