I have a Garmin RV 760LMT GPS unit. This RV GPS uses my rig's dimensions in determining the route to plot. Garmin has a free map program called Basecamp for both Windows and Apple PCs that uses the same map database as your Garmin GPS unit for planning routes, etc., and allows you to upload or download route and track data between your computer and GPS. There are tutorial videos available to get you started.
The software has its own less detailed base map so you can check it out if you don't have a Garmin GPS. However, you'll need a Garmin GPS for the full street-level map.
2015 Wildcat 282 RKX
2011 F350 Lariat, 6.7 L. Diesel, 8 ft., SRW, Reese R20