Vehicle class, or object?

Lets say that I have a river barge model. I want my character to be able to walk around on it, but also be able to take control of it.

Will the mount on a vehicle object allow my character to move around, or should I make the barge an object, and write some code to allow the character to control it's movement?

I guess what I am asking is can a person both be mounted on a vehicle, and also walk around on it?

I am least worried about figuring out how to control the vehicle, because it will require a lot of srewing around no matter what.

Thanks.