Maybe there is a ladder inside the pipe that Mario climbs/grabs on to after jumping in? Or, we could always use the elevator theory here, too.
.. I feel like we've discussed this before, earlier in the thread. Have we gone full circle with Mariology? Probably not..
Starmen coming from the Star Road, that's an intriguing thought.. It would make sense, since most of the stars (all the stars?) we've ever seen in the Mario games have had eyes. The star that picked the Geno doll in Mario RPG didn't have eyes though..