I think this is one usage of "fail forward", but not the only one and in my view not the primary one. "Fail forward" in a game like Burning Wheel is a way of adjudicating a character's failure to meet his/her goal."fail forward" presumes that the PCs will meet their goal (travel to destination X) so that play does not grind to a halt, even if they fail the SC
In BW, action declaration requires a declaration of both intent and task. If the player's check succeeds, then the PC succeeds at the task and achieves his/her intent. If the player's check fails, then the GM has to establish the consequences of failure, and is encouraged to focus on intent as much as or moreso than task when narrating failure - so the character may succeed at the task but not realise the desired intent.
In the context of a travel skill challenge, we know that task is travel from X to Y. But what is intent? If it is simply make it from X to Y, then maybe there is really nothing at stake at all - and then the GM might just "say 'yes" and/or call for some simple roll to determine what/how many resources are lost (this is pretty much what [MENTION=82106]AbdulAlhazred[/MENTION] suggested upthread, I think).
But if intent is arrive within time or arrive without having spent all our rations or whatever, then that might provide a focus for the narration of failure (similar to [MENTION=6696971]Manbearcat[/MENTION]'s famous example of the character climbing the mountain with the intent of finding the pudding (?) at the top, and running the risk of losing his/her pudding detecting wand in the course of the trek).
For there to be a chance of not making it from X to Y at all, then there needs to be some reason in the fiction why the PCs mightn't make it, and that should be part of the intent eg we travel from X to Y without getting lost, or we travel from X to Y without being caught by the Ringwraiths who are hunting for us. If there is nothing of this sort that emerges from the fiction, then that makes it a good candidate for "saying 'yes'" rather than framing a check.