Might see you on the ride then - although I will be a bit slower than 15mph. 150 (actually it is 160) is my longest ride yet. i will probably be on my focus cayo with a mate on his Felt.
A number of navigation options on Iphone by downloading various apps - I have downloaded some OS maps that i can plot the route on. Takes a bit of time to get the route on the phone though, but I guess that's the same with any GPS. Bigest problem has been battery life, but have now got an external battery so should be Ok.
Don't know if you have seen the route directions yet, but as the organiser says thay are a bit non standard for audax. On the one hand in more detail than usual, but on the other not sure how easy they will be to follwo on the bike, so i am pleased to have a back up.