Mistyping Mixing my metaphors is a speciality
Yeah I use ridewithGPS all the time - creating a route is dead easy - you just click on a place to start the route and set it to follow roads clicking on route points as you go - good idea to have the routesheet to hand if you're keen on making sure you follow it to the letter - make sure you save it as you go along - some of my computers are slow and get hung up on a long route occasionally. It takes a while but not desperately long - much less heartache than getting lost on a 200 k audax!
Once you've saved the route there are several options for exporting it as tcx, gpx etc. If you go premium you can even directly import it to your garmin.
Bikehike is good too - sometimes I use this instead when my computer won't play ball.
If you're lucky someone else will share the route they have created - Bikey Mikey if he's riding is a great guy for this as he does a solid GPS route every time. Asking for a gps is no worries usually, I'm happy to share mine once I've done one and plenty of others are too.
Avoid temptations to use Garmin's software by the way - that's generally terrible although basecamp can be OK if you need to compress the route for bragging rights on Bikeradar or such if that's your bag. Long audaxes can generate massive files that are tough to otherwise upload to the various sites such as MMR, strava, bikeradar etc. (although that's a post-ride issue not navigation).