If you are a new rider, and don't have a bike yet, 24 miles each way is not a good plan. It's just too much to jump into, unless you are physically exceptional.

The idea of using a folding bike that you can take onto the train is the best compromise IMO. That way you can adjust the distances as you become stronger on the bike or more motivated to ride more.

Google Map's estimate is probably not wrong for an average bike rider. I wouldn't base my planning on being able to make it in under 2 hours were I you, not at first.