newbie needing training advice....

hi, i wonder if anyone can help me? I enjoy a little bit of recreational cycling, ie cycling 6 miles to tesco and back with my son in his trailer behind me, and probably the furthest ive cycled is maybe 8 miles.....
so, for reasons best known to myself, i signed up for the 2012 moon ride, london to brighton 60 miles......
Help! how do i train for this?! i'm determined to do it, but at the same time im worried ill find myself excuses as to why i cant cycle etc.... i have a dawes discovery, which i assume is an ok bike for doing this sort of ride, although it does need a slightly more comfortable saddle!
Any training i do will sometimes be accompanied by my son in his trailer, so obviously he will get bored/cold if im out for hours, and i cant always leave him at home.
I live in Ipswich so if anyone can reccomend a good route in that area it would be helpful, also should i join a cycle club, and should i do any other exercise to help me? im not a particularly fit person
thanks! kate

 

i don't think it is a good idea to go for hours with your son in the trailer,
you will need to find a place for him for those longer training rides,
think of your ride in terms of hours not miles, so at a low pace 60 miles means 4 to 5 hours, that is what you are training for, increase gradually your training rides until you can finally ride for 4 hours for example one Sunday morning, then you are ready !