Training for the x-country ride

I have been riding my bicycle 6 days per week since Jan. 2010 and it is now June and my ride is less than 2 weeks away. My weekly mileage has been between 300 and 350 miles per week as the training log suggested from the company I am riding with. So far my yearly mileage is over 5000.

I am riding from Astoria, Oregon to Portsmouth, New Hampshire for a total distance of 3650. This will be a 50 day adventure with 5 rest days, so the actual ride will be 45 days with the daily average mileage being 86. America By Bike is the company I am doing my ride with as we are staying in Motels every day and they take care of hauling the luggage, mechanical support and rest stops daily.