Dalmeny to Kirkcaldy walk

I'm training for a charity walk. Total distance of this one will be 20 miles. However, can drop out at any point between start and end (Google your own preferred transport options). Route will be Forth Bridge, Inverkeithing, Aberdour, Burntisland, Kinghorn and Kirkcaldy. Speed will be around 3mph. Is a cheap spoons for celebratory beverage if we make it to the end.