Well, some railnutz are attempting to do this 'LIRR Ultimate Ride'. I believe someone attempted it this past weekend and got mixed results, due to the snowfall.
If anyone wants to follow this subject in more detail go to:
www.subchat.com
BTW, the idea of the 'Ultimate Ride' started with a group of NYC Subway buffs who got the brainstorm to ride every line in the subway system on a single fare (i.e., without leaving the system). It was not done as an indurance speed-test, but the Cable-TV crew that taped their exploits made it sound that it was.
Again, the idea of an 'Utimate Ride' in and of itself isn't a bad idea, just not good to do in winter weather...too many factors (mostly the weather) to consider to make it a worthy endeavor...