thanks for the tips! Just what I needed.
I probably am mad, but we've got a roundabout here that I commute through every day, though it's only one lane.. I've been in multilane roundabouts in Martinique and Kenya, they don't seem so bad... I know I will be tired, but I think this will be fun anyway. The roads all look reasonable, even the ones marked as busy. Not as crazy as some stuff around here, for sure!
My only worry is that it plotted a really confusing route. I think I'll get it, though.
Any more thoughts are greatly appreciated!
http://london.cyclestreets.net/journey/145959/