Overland Design: Travel Times

Last night, I broke out Excel and GURPS Dungeon Fantasy 16 - Wilderness Adventures, and started figuring out the geographic scale and layout of the land between Town and Dungeon. This was an interesting process that required me to look up vehicle speeds in GURPS Low Tech, since Dungeon Fantasy doesn't really concern itself with that sort of thing, which is kind of surprising. You do need a way to haul your loot home, after all.

Once I had all my travel speeds, I set out to describe the area around the dungeon, and came up with a couple of things I like. First, I've been watching Bordertown on NetFlix lately, so I decided I wanted a big lake. This also fit with how I've drawn the main entrance into the dungeon - a castle on a rocky islet connected to a manner on the coast. So I looked up big lakes in Google and found out lakes get pretty darned big! This gave me some ideas.

What if the the Dungeon is at the opposite end of the lake from Town? This would allow for some serious boating over a deep, dark lake with God-Knows-What in it. Why would adventurers risk this? Because boating is fast. They can also hike around the lake, but what if that takes days, but you can cut right down the lake in a day or two tops? This gives players options, and that means agency. I liked it.

So we have a giant lake, and the fastest boats can make Move 4, but most are Move 3. In a 12-hour day, this works out to a typical boating distance of 36 miles per day. After looking into existing giant lakes, I decided to double this to get the length from Town to Dungeon as the fish swims. The party will need to either spend the night adrift (the lake is unfathomably deep; seriously, look up how deep lakes can get) or beach and camp on shore. The latter will require making and breaking camp.

Next, I figured there are two ways around the lake - the "North" shore and the "South" shore. I haven't decided the actual orientation of the lake, so this nomenclature is just for convenience. Continuing the theme of maximizing player agency, I decided the terrain along the north and south shores would be different over most of the traverse.

Right outside of Town, the land isn't wild yet, just rolling hills, and by the dungeon, it's similar. This doesn't last forever, though! Along the north shore, the hills grow rougher and wooded. Eventually, those hills give way to mountains, and the mountains get difficult enough that the passes climb upward above the treeline. This path descends again down through the forested mountainside into hills and then through the ancient clearing surrounding the Dungeon. The southern approach is mostly wooded and includes about 20 miles of swamp, also. This will let the players decide the kind of encounters and hazards they want to deal with.

Now, the next task was deciding exactly how much distance is covered along each path. I want the northern and southern shores to be equally appealing in terms of time requirements so the players are just choosing between types of hazards and not how many random encounter rolls I'm going to make for them.

So I set up a spreadsheet to calculate typical travel time based on basic means of travel - hiking. I assumed that in winter, players would get their PCs snowshoes. Then I grabbed the ratio of length to width from Lake Baikal, since that's roughly the shape (not size!) that I'm looking for and found a rough estimate of lake circumference. The next step was tweaking the actual distances for each leg of the journey until the north shore and south shore took relatively equal lengths of time.

Now you'd think this is the end of the story, since now I know how long it takes to get to the Dungeon, which terrains they pass through, and for how many miles, so the times can be modded by gear and rolls, as need be. But no! Some things revealed themselves in the tweaking of distances. The northern shore is shorter than the southern shore, so this lake must be crescent shaped. Moreover, the northern shore path is shorter than the length of the lake, so that path must really cut up across the mountain, and the lake wraps itself around that mountain. The forest extends down the mountain and into the hills below; it might just be a valley, but I'm not sure yet.

This process may look long and detailed and involved, but it yielded a lot of good information. Not only can I now handle the overland portions of sessions, but I now know the shape of the land around the dungeon and Town. I guess now I just have to make a map, encounter tables, weather tables, more dungeon levels, some monsters, a rumor table . . .