When you're writing an adventure in advance of a session, and the structure of the adventure requires the characters to chase a Macguffin or otherwise head to a particular place, and you're in a situation (such as for convention play) where you can't custom-tailor a baited hook that you know a specific character or player will gladly follow and beg for more, what techniques do you use to avoid obviously railroading the characters or falling into the "sit back and let me read you a story" pit?
(Especially when a) it's blindingly obvious up-front that there's a lot of danger involved in the chase, b) any incentives that would be large enough to make the danger worth it would likely wreak havoc with the rest of the scenario, and c) the characters will almost certainly realize that they have to survive first in order to collect the incentives.)
P.S. "Let the characters wander aimlessly or wherever their whims take them, and just ad lib encounters for four hours real time", while a valid approach for some people, is not practical advice for me, as I typically can't ad lib my way out of a wet paper bag with a seeing-eye dog and a double yellow line leading the way.
Feudalism: Serf & Turf