DISCLAIMER: I know the developer and I probably had some small hand in suggesting some things, but otherwise have no skin in this. I even paid the Pro fee (out kindness and feeling guilty about not donating soomer).
The Kurviger.de web site, which started as a twisty route finder for European riders, grew up to the point where it can handle anywhere roads are found on a map. That is, you can go twisty-hunting here in the good ol' USofA, the UofK (OK, UK), or oh... Canada...
The site starts in German unless you use
www.kurviger.de/en or just choose the English option on the German page.
Kurviger.de can draw "OK, I'll accept some slabbing" routes, "don't want no slabs, don't want no corkscrews, do want curves", or "bring it on!!!" routes. They can be modified in lots of ways, and the results can be exported to anything that can handle a .GPX file - such as Base Camp. Or the route can be saved with a unique URL which, of course, can be shared. This site has a lot going for it, but... kinda sucks to carry your laptop, a satellite hotspot, and gen set to keep everything going. But wait...! Now there is... "Kurviger!" for any AndyOS phone.
Kurviger! does all the neat stuff the web site does and you can take it with you. The free version is fully functional, does the routing, etc. The Pro version adds voice navigation, improved map imagery (3D shading for terrain), extended round trip routing (600 mi, 1000 km), alternative routing, and a turn adviser to point out "can't turn into a one-way street" sorts of things.
Kurviger! is free, Kurviger! Pro is $6.49. IMHO it's one of the few apps that's more than just another "Talking Tom" or "Beer Chug" app that wears out after 5 minutes.
Almost forgot... Play Store - search for Kurviger. Easy-peasy.