Steve, if you go to the Route Guides page, down at the bottom you'll find a whole load of EV routes already in CT. 

https://cycle.travel/routes

You haven't said what you're looking for but if what you seek isn't there, the routes are available for download on the EV site. https://en.eurovelo.com/#routes-and-countries

I wouldn't attempt to import them into CT directly, but I'd use the "Trace" feature to overlay on a map and recreate the route from that.

If you're not aware, the EV routes vary greatly in terms of quality (and interest) from province to province, never mind country to country. Some sections are little more than a line on a map. Depending on your ideal route, I'd trust CT's suggestions more than the EV planners.