Here are some of the tools I use regularly.
- Strava Heatmap: https://www.strava.com/heatmap
- Ride with GPS: https://ridewithgps.com
- Komoot: https://komoot.com
- Gaia GPS: https://www.gaiagps.com/ - more map types
Dustin Klein interviewed Ryan Francesconi of OMTM on how he builds routes with a lot of good philosophy on route building: https://www.youtube.com/watch?v=6GTuSFvRPtw
- Historic Snow Maps: https://www.nohrsc.noaa.gov/interactive/html/map.html
- Epic Ride Weather: https://www.epicrideweather.com/ - see how weather will change throughout the route
- Washington DNR Lands: https://www.dnr.wa.gov/sites/default/files/rec-map/index.html
- Bikepacking routes https://bikepacking.com/bikepacking-routes/
- Oregon Bikepacking http://www.oregonbikepacking.com/
- OMTM Routes (Wa/Oregon) http://www.omtm.cc/
- Ride with GPS Ambassador Routes: https://ridewithgps.com/ambassadors
Any other good resources?