The primary resource always being spent in Overland actions is Time. The party will have to spend Time. Other resources may be spent - food, ammo, health - but Time will always be spent by Overland actions. So much so that usually each day is broken into sections of Time - 1 hour, 4 hours, 6 hours, 8 hours, called a Watch, Quarter, Phase, whatever. Whatever you choose becomes a chunk of Time the party spends doing something Overland. This is why you chunk it in the first place, because Time is going to be spent, so you make it neat and packaged - you "itemize" it - to be traded for something else.
Thus, the question of Overland becomes: how do I want to spend my Time?
All Overland actions - meaning those actions one takes when presented with a large stretch of territory and large chunks of time - boil down to Travel, Explore, or Acquire.
Or Explore, Acquire, Travel.
Or Acquired, Travelled, Explored.
Or Explore, Travel, Acquire. I find this option humorous.
I'm sticking with TEA.
Option 1: T(ravel) - A → B
Travel is getting from A → B. That's it. You start in one place, you want to get to some other place, and you know where it is. You travel. It can be on foot, by boat, by spaceship, whatever. Each has its own setting, speed, and availability. It is the balance of Time and Another Resource which provides options for travel.
Option 1: Safe but Slow - There's a well-guarded road between A and B, but it winds. It is slow - it'll take an extra day of travel, but you'll be safe for majority of it. What's the balance? Time vs Health. The party has opted to sacrifice Time to stay healthy. I can't blame them.
Option 2: Middling - There's a guide who knows side trails which connect A and B. She'll take the party, for a fee, and can promise relative safety and arriving on time. What's the balance? Time vs Health & Wealth. The party has opted to sacrifice wealth, and potentially health, to save Time.
Option 3: Fast but Dangerous - If you cut through the Woods of Death and Destruction and All Things Horrible, you'll save two day's travel. Of course, as the purposefully over-the-top name makes clear, it is dangerous to one's health. What's the balance? Time vs Health. With this option, the party chooses to sacrifice health for Time. Best of luck to them.
It would be wise, when it makes sense, to provide at least two basic options for travel. It grants the players meaningful choice within Travel. It's the port with the fortified ship, the merchant's boat, and the crusty old sailor's "boat".
Option 1 will get to the right city port after a few stops.
Option 2 promises safe travel and a straight shot for a hefty price.
Option 3 swears up and down he knows these waters better than any other and will do it for the right kind of liquor.
The party is balancing Time with Another Resource. Which they favor depends on the party and the circumstances.
If you want to look at these options a different way, it is a balance between short-term and long-term. Option 1 has short-term benefit - safety. It also has a long-term detriment - you arrive a day late.
Option 2 sit in-between short-term and long-term.
Option 3 has short-term detriment - danger. It also has long-term benefit - you arrive early.
Of course, you can always be
very boring totally fine and simply say, "You get there". That's fine. ToTaLlY fInE. "You get there X hours/days/weeks later".
None of the above are mechanics though, as there is no mechanic to travel, per se. There are complementary mechanics though, known as Getting Lost and the Random Encounter.
Getting lost is the greatest threat to Overland action because it wastes Time. However you go about determining a party is lost, this is the worst option for a party Overland because they are spending their Time on nothing, effectively. They aren't getting to B, they are just wasting Time. As the greatest threat, there should be ways to mitigate this. The two most common are maps and guides. Both cost something, so what's the balance? Wealth vs Time. A party who values Time will cough up what is necessary; a party who values wealth will take the risk. The other threat of Getting Lost is its ability to compound problems with the other mechanic, the Random Encounter.
The Random Encounter
Random encounters are supposed to simulate a living world. They happen in real life - a deer down the trail, a bicyclist crashes into your car, a stranger strikes up a conversation, a storm breaks over your head. The party is traveling through a living world, so things should happen to them. Weather phenomena should happen, animals, monsters, and people should cross their path, things should be stumbled upon because the party aren't alone in the world.
Random encounters are usually used as a resource drain. What resource? Health and wealth are the two main ones - damage to hit points, food stolen or spoiled, various items broken or lost. However, not all of them have to be. For example, a conversation with a dryad drains no resources, unless you are tracking minutes, ya psycho, but it provides useful information for later on. They can be used to drain resources, flesh out the world, encourage player interaction around the table, break up a lull, introduce a plot hook, and so on. They have both in-game and meta uses.
How often should they happen? You do you, but I think they should be rolled at the start of each of your Time Sections. If one should occur, it'll occur within that Time Section. The more Time Sections spent, the more random encounters should occur, so a travelling party with somewhere to be wants to spend the least amount of time possible travelling.
A party's stealth and speed influences their frequency, and usually are a balance within themselves. Rarely is the rushing party the quiet party. It's another balance of Time and Another Resource, usually Health. Funny how that keeps showing up in Overland.
Whatever the Random Encounter is, it would be wise to link them to the party's goal. It encourages interaction.
I'll be discussing Explore and Acquire in upcoming blog posts. Travel is the easiest one, and nothing I said here is new or revolutionary. Despite being simple, there should still be meaningful choices throughout, a balance of Time vs Another Resource. Otherwise, if all the options are the same, there's no point in having options at all. The Overland section of the game demands the party spend Time and balance it against Another Resource. The player's choices should have negative consequences relating to the resource they sacrifice and positive consequences relating to the resource they favored. That being said, when those consequences happen could be short-term or long-term.
Random encounters can be that consequence, but aren't limited to resource drain. Random encounters have their uses in-game and around the table. Make a reliable list of them, adapt them to the party's current goal, and use them appropriately. That last one is the kicker, because you only learn that through experience.
O Void, please enjoy this intermission to stretch your legs. Maybe get some popcorn or candy. Let me know what you've thought of Act 1.