The Alternative Hexcrawl mechanics I've been knocking about seems to provide a very gamist absolute of make your roll and move or fail your roll and stay put. Going strictly by mechanics that's what seems to be what is happening , it isn't.
Beyond the desire to have wilderness travel be more involved I also wanted to incorporate some of the rules that have been in D&D related RPG for decades (getting lost) while giving room to add to the experience with a mechanic that provides a notable action that gives a time break to ask questions and for player and referee to offer input.
The travel roll is to make meaningful progress through and out of a hex, a failed roll doesn't really indicate no travel on the part of the PCs, it implies no meaningful travel. When a roll is failed there are obstacles, distractions or missteps taken on the part of the PC's. Player choices and actions could mitigate the "failed" rolls.
So why did the travel roll fail and are there consequences that follow the failed roll? How can the players cancel a failed roll (or get a re-roll)?
Each terrain and composition of an adventuring party will vary as to why the party didn't make progress while traveling so there's room for the referee to be creative. There's a host of replies to simple question of "Why?": "You are lost","You've been following the wrong trail","The trail ended and there is no clear alternative","A watercourse/body of water blocks your route","There is a steep slope too risky for travel","A chasm blocks your way","Some of the followers have wandered off course","The mules aren't proving to be cooperative", "A horse has thrown a shoe"," A wagon is stuck", "Bill lost his boots in the mire seriously slowing everyone down","Brother Misk insists on completing a ritual at the way-shrine", "The scouts really screwed up."
Responsive action on the part of the players could earn them an immediate re-roll or a notable bonus (above one for persistence) in their next travel roll. The impact of player reactions should be measured by the scale being played. Building a bridge or rafts to cross a troublesome body of water isn't a quick action if we are dealign with hexes that can be crossed in but a few hours. Wilderness travel and what is significant should vary with scale.
Player action can also offer bonuses to the travel roll in the first place. If you have a party traveling with a number of wagons and loaded down pack animals there isn't going to be a lot of wiggle room for maneuver unless of course the party has quicker moving scouts and makes use of them and then small local difficulties can be spotted and avoided before the party if hampered. Taking note of local landmarks is certainly important and beneficial and may earn the party a bonus to travel in some environments.
If progress is hampered by NPC cut-ups the players can simply disregard or cast-off the NPCs leaving them to flounder while the party moves on earning the party a re-reoll to travel. This would of course have consequences as NPCs may be lost, refuse to follow or fall victim to other hazards.
Sometimes a failed travel roll can be based directly on the actions of the PC's. Actions such as avoiding a suspected dragon den, trying to keep out of sight of a watchtower, avoiding patrols, taking caution to avoid being sky-lined can all severely hamper travel by effectively closing off routes travel. The ever popular actions of "grazing the horses as we go" and" hunting along the way" are easy marks for slowing travel and those actions as many others should likely earn the party a penalty to the roll in the first place.
There shouldn't be a hard and fast reply to "Why didn't we get there yet?" tied strictly to mechanics as each referee is the best authority on what the campaign and adventure setting is like and what' s important in that specific game. Sometimes the answer can be a simple as "you didn't get there yet" and other times progress can be checked by a wide range of hazards the player may or may not be able to deal with. Travel itself can be an adventure and exploring "why" adds detail and interaction to an RPG campaign.