Ken rode when I did it 2 years ago on a setup with 26" wheels, slicks, and an internal 3 speed hub or some wacky thing that broke on him like 50 miles into the ride.
He caught up with a bunch of us later, and then it ended up being the two of us for a long time, then we lost each other on the 3rd day. He thought I had beat him the whole way into Philly but we ended up crossing paths and not seeing each other.
He made it to Philly around 5pm or so Sunday and I didn't come in until 11:15 because I was so beat I just didn't give a shit anymore and pretty much limped all the way into town, and took many many breaks along the way to enjoy myself.
I was going to ride that with my own mountain bike running slicks and clamp these really wide aerobars I have to the handlebars and really look foolish LOL... But I found this cannondale touring bike on Craigslist the week before the race and rebuilt it a few days before the race (which was the main reason I was so exhausted). Other than a 2 mile test ride, the 400 mile ride was my first experience on that bike and my positioning was off, and it took me awhile to get the right handlebar combo I liked, and seat position worked out later on.
I absolutely love my Cannondale touring bike though for rides like this... with 3 bottle cages, and a Camelbak... front and rear rack-mounts, and cantilever brakes, (and you can run a triple crank on it, but I have switched to a double since)...
I can go about 10 hours before having to make a water stop if I really wanted to. I only ran into one instance where I had no water and that was because I was using my large backpack and the water pouch is a pain to cram back in when full. This time I am using my regular camelbak and keeping it filled when we approach the more rural areas where the water and snack stops are several hours apart.
If you bring your MTB, you will get up every hill with no problem, but absolutely make sure you have a triple with a large chainring or I will just be a blur when I come flying by in my aerobars down the other side of the hill MUAAAHAHAHAHAAAAA...
My strategery is a lot different than everyone else's and my excessive weight works in my favor with my technique LOL...