This will be my 2nd year doing the PMC. I'm riding the 84 mile Wellesley to Bourne. Its a great ride with great support and tons of wonderful people - no matter how fast or slow you ride. For training this year, I'll ride 2 nights a week (one 19 mile and one 15 mile on rolling hills) and a longer ride on weekends. Just get out and ride as much as you can and increase your long ride every week or two.
The hardest part for me is the fundraising. Last year I raised just over 2400. This year the minimum is 2600. I've already started this year's fundraising.
Good luck with it all - you'll really enjoy the PMC weekend.
There's no place like home!