Four months should be enough to get you ready for the Graperide! I hadn't done a lot of cycling before starting my training for it. I signed up to a seven week programme and my longest ride before the race was only about 60km. I wouldn't recommend that approach - an injury limited my time on bike halfway through the training, but it shows it can be done. I was already reasonably fit from running, but the Graperide's not too hilly, so I think you can do it!

It would be great to meet up with some other TE members down there. I tend to mostly lurk on here so it would be a good way to force to be myself a bit more social.