We generally have great vacation experiences, we've never even been rained on in 5 trips to WDW. But in 2008 we rode Amtrak from southwest Iowa to Colorado. Iowa was experiencing floods at the time and the train was 3 hours late to pick us up.
That wasn't the bad part though. Because of the flooding, our train back to Iowa was cancelled. Amtrak instead provided us a bus from Denver to Omaha (which is about 100 miles from where we originally boarded in Iowa). They loaded the luggage underneath the bus. The driver started to pull away when my 9 year old daughter said the sides were still open from putting the luggage in.

..DH spoke up and the driver stopped to close the sides of the bus. So a luggage disaster was averted at least.
This was also the first bus trip making that route, so the driver had a Mapquest printout. A passenger offered to stay up all night and help him navigate. This wasn't an interstate trip- we had to stop at every little train depot in CO and NE in case anyone wanted to get on or off (no one did). Though at one stop, someone else in a car approached the driver because they were lost and wondered if they could follow us to Kearney. The driver said, sure, then got on the bus and said "Where the hell is Kearney?"
It was an overnight trip, but I had an awful hard time sleeping sitting up on a bus. Plus the a/c was blasting and the driver didn't know how to adjust it so it was cold besides. Eventually the driver met his quota and had to switch with another driver at a hotel, and the new one knew how to run the a/c.
Finally we arrived at Omaha and my dad was able to come over there and pick us up. Some others had to rent cars to get back to their homes or the depot where they left their car.
It wasn't pleasant, but it sure could have been worse. We've been lucky.