Travel Rules

1. The trip to the party's destination will require a total number of successes before they arrive. The total number of successes necessary depends on how far they are traveling and how difficult the area is to travel through. 
2. Each day of travel adds one required success over easy terrain (regularly-used roads, towns, plains or fields). Moderately challenging terrain (hills, swamps, bogs, obstinate storms) adds two, and highly challenging terrain (steep mountains, other planes, under the sea) adds three per day of travel.
3. Once you have determined how many successes the party needs to complete their trip, the party will take turns in initiative order narrating how their character helped overcome an obstacle or solve a problem on the way to their destination. 
4. On their turn, each player selects one skill they are proficient in and rolls against a DC 15 check. Success marks one success off of the required total for the trip. 
5. A player cannot choose a skill that another player has already used until they run out of choices, in which case they can choose any skill they are proficient in again. 
6. Rangers with the "Natural Explorer" class feature have advantage on these skill checks, as well as the following features if traveling for an hour or more: a) difficult terrain doesn’t slow your group’s travel, and b) your group can’t become lost except by magical means. 
7. Alternatively, a player can choose to expend a class resource instead of rolling a skill check for an automatic success. Class resources that can be spent in this way include spell slots, ki points, action surge, channel divinity, bardic inspiration, rage, and superiority dice. This is not an exhaustive list; if a player makes a good case for how another class resource not included in this list can help the party on their travels, it should be allowed. 
8. Players expending class resources will remain without those resources until the party has reached their destination; they will be down spell slots etc for any random encounters that occur on the trip.
9. At the bottom of initiative, the DM rolls a d20 against a random encounter check DC to see if a random encounter occurs. The DC for the random encounter check begins at 15 and goes down by 2 each round of initiative over the course of the trip. The DC also reduces by 2 for each critical failure rolled by a player. The DC resets to 15 once a random encounter occurs, and the process continues (assuming the trip is long enough to require multiple rounds through the initiative track).
10. Once the party has accumulated enough successes to equal the number of required successes determined at the outset of the trip, they have reached their destination.