Let them roll for journeys. Dont let them push. Unless something is REALLY at stake there is no reason for them to push.
99%
No pushing journey
rolls, period.

Now, the mishap that results from maybe not passing the roll, that's probably a dramatic moment that has stakes enough to justify the
push.
Going off what Fenhorn said, journey
rolls are already different mechanically (often and routine
rolls), they're easy to partition in this way. Keep pushing to moments of actual risk. Extended tasks like journeying or crafting really aren't a good fit for the mechanic.