My thought is that you should have no problem with it given your regular cycling routine. I have only been riding regularly for a few months on a MTB. I will do 10 mile loops on my lunch break a couple of times a week and had gone on 2 20 mile runs before taking my longest trip. There was a charity ride near me and I signed up for the 48 mile route. This was my first charity ride and my longest ride.

No problems for me. There were well planned rest stops about every 15 miles I believe that were stocked with goodies. I felt great for most of the ride, but the last 5 miles sucked due to a combination of fatigue and riding directly into the wind.

On a related side note while I was preparing that morning in the parking lot I was chatting with an older gentleman. He asked if I was planning on doing the MS150 and I replied that it is on my list for next year. He stated that he had done it for the past 20 years and also shared what he called an inside joke. It was that if you can ride 20 miles then you can do the MS150.

Good luck and congrats on getting back on the bike and doing good for yourself.