I normally am a really careful planner when it comes to giving these sorts of technical talks, you wouldn't catch me going out the night before.
I had assumed that the train would either carry the one vegetarian meal on the menu, or accommodate. After a first day of eating cold bread loaves with margarine, an altercation with an uncompromising attendant on the second day, I managed to secure myself a "Steamed Russet Potato A-la Tomato Sauce", for the third day aboard.
I had also assumed that the venue would carry palatable vegan options, or that I could cook my own. After missing the Strange Loop meal service twice in a row, due to talk scheduling conflicts, I managed to queue long enough to acquire the remaining scoop of utterly awful vegan soup, and then returned to stealing whole fruits from the gym and eating them in my room, which I was content with. The problem that wasn't apparent at first was that eating sweets all day kept me up all night.