I have looked at Ridewithgps, Mapmyride, Garmin Connect and a couple of others but in my opinion Plotaroute is the best for touring.
It is quite new I think and when I first looked at it was a bit of messing about transferring routes from the PC to the Edge Touring. But that has been changed and it is now only a couple of mouse clicks and you get turn by turn routes uploaded onto the Edge Touring.
The other things I like about the Plotaroute which I like is that you do not have to keep flicking in and out of Streetview like you do with other route planners it is built into the plotting screen.
You can also plot a route which is on road and then sections offroad and they are all uploaded as turn by turn points.
I have just been out on a 16km ride to test it out and it was excellent. It took me 2 minutes to plot the route on the PC, seconds to load it into the Edge Touring and off I went I plotted the route so it would go along roads, small tracks and forest tracks and it didnt put a foot wrong. I even rode off the route and the Edge Touring got me back on route without a problem.
There is lots on Plotaroute which I dont know but even the basics are great.
Sorry for going but I like to Spread the word when I find something that I like.
Here are some of the tracks I rode today.
A small track between summer houses.
Unmarked forest tracks
Country tracks