I use the National Geographic Topo State Serise for CA. I have been using it for close to a decade and LOVE it. I spend way too much time on that program. I used it for years planning mountain bike, backpacking, and mountaineering trips. I have started using it recently to plan road rides as I am transitioning into road biking. Someone on Road Bike Review taught me a trick for drawing straight lines in TOPO when using the Route tool. The Route tool works great for drawing freehand lines on curvy roads and trails but is terrible for straight lines. Hold down the shift key while using the Route tool, move the mouse to a new location and release the Shift key, the Route tool will draw a straight line from the anchor location to the new mouse location. Very handy.

You can make nice looking maps, upload waypoints to a GPS unit, download waypoints from a GPS to TOPO, and connect a GPS to TOPO to track your current location in TOPO. You can also build a profile of your route and analyze the entire route or sections of the route to determine the grade.

I find using the Route tool in freehand mode to be about +/-10% accurate for distance. My accuracy has imporved not that I am zooming to 300% and using the Shift key when drawing my routes. It takes much longer but produces excellent results.