Formulas

In the official rules, an average character with no encumbrance can travel 50 miles in 14 hours (with a few pauses) over a flat terrain.

The Grand Raid (a hiking event set in La Réunion, a French island next to Madagascar) is a 87 miles (140 km) long adventure, with more than 8000 yards worth of going up and down (I'd say a x0.5 modifier for broken terrain). The best hikers do it in 18 hours. Assuming those guys have the Fit advantage, a fair score in Breath control, and a good score in Hiking, it should be pretty well consistent with the rules, and I'm actually thinking that they're even better than this.

In-game: considering a Move 5 character, x0.5 terrain, no encumbrance, you get 25 miles per day (a day is 14 hours of hiking). You'd need about 48 hours of hiking to finish the raid, which is what most people do (the upper limit is 60 hours). If you succeed your Hiking rolls, have the Fit advantage, and push yourself to the limit (not fully recovering your FP every 3 hours), I think you can reduce those 48 hours to something like 30 hours. In order to get down to 20 hours, you'd have to increase your stats, which sounds quite okay.

Note from Fred: when you say "which is what most people do", "most people" means "most hikers participating to the race". And these hikers are trained athletes, not week-end walkers. They have also the Fit advantage and a good level in Health and Hiking. And you forget to mention a very important point: they are so exhausted at the end of the race that they are forced to rest one full day at best. They can't do that every day, on a regular basis. That's why I find the GURPS rules unrealistic.

Another famous french track is the GR20 (located in Corse, another French island in the Mediteranée Sea). Once again, it's on a fairly broken terrain (more than 10000 yards of ups and downs), and its total length is roughly 125 miles (200 km). You have to be quite prepared to do this, but if you're ready, you can do it in 15 days, with 6 hours of hiking per day. Most of the time you'll have Light Encumbrance, maybe Medium Encumbrance during the first few days.

In-game: considering a Move 5 character, x0.5 terrain, halving hiking days (BasicSet hiking days are 14 hours), you get 12.5 miles a day. If you're lightly encumbered (as per the rules), you go down to 10 miles a day. After 15 days, you've traveled 150 miles. But obviously, you're going to make a few Hiking rolls along the way, which will increase this distance. I guess you can say that the official rules are a bit optimistic, but then again, that's what Kromm said (the average GURPS character is an average hero, not an average person), so we already know it!

Hiking days

The BasicSet rules are based on a 14 hours hiking day (of which only 12.5 are actually spend hiking). Some people find this unrealistic. An average hiker will, most of the time, walk for 6 hours every day, with Light Encumbrance. At this rate, it's pretty easy to keep on going for several days.

Most people with some hiking experience will state that hiking for 14 hours a day is a lot, and only trained people will be able to keep this up for several days in a row. The average guy (even the average hero!) will find this quite hard to accomplish, and won't finish the day with only 3 FP missing (this is according to a friend of mine who was an instructor in the French army, and used to lead rookies in forced marches).

Conclusion

It seems that the BasicSet formulas are correct, but are simply based on an unrealistic hiking day. This is okay if you're playing in a "fairly heroic" campaign, with no more than 2 or 3 days of hiking at a time. Otherwise, simply use the same formulas, but bring the basic hiking day down to 7 hours and 25 miles. Above this, apply additional fatigue costs.

House Rules

Various solution have been proposed to correct the rates for inexperienced hikers, below are three examples:

• Multiply hiking rates by x0.5 or x0.75
• Use 8 hour hiking day, overall distance covered is Move x 5 in miles including rests. Fatigue expenditure is the same as combat but using hours as time unit. To continue hiking apply Long Task rules, Basic Set p.346. Each hour add Move x 0.8 miles, or Move x 0.7 miles including rests.
• Characters can hike for a number of hours equal to their Hiking skill, eventually defaulting to HT-5. Hourly movement is Move x 0.8 miles, or Move x 0.7 miles including rests. Fatigue expenditure is the same as combat but using hours as time unit. To continue hiking apply Long Task rules, Basic Set p.346.

An official rate per hour?

(A note by Gollum)

If the hiking day represents 12.5 hours of walk, and if the hiking rate is move x 10 miles per day, then the hiking rate per hour is:

• (move x 10) / 12.5 = move x (10 / 12.5) = move x 0.8 miles per hour.

So, even if it is not (yet) written in the rules and even if it has not been explicitely said by one of the authors, this rate can be considered as the official rate per hour.

Used with the Long Tasks rule (page 346), it will incite the player characters to hike only 8 hours a day, which gives:

• move x 0.8 x 8 = move x 6.4 miles per day.

This new rate seems more realistic, especially when the player characters walk several days in a raw. Of course, in case of urgency, they can force themselves to walk 12.5 hours per day. But they know what they risk now: a HT-2 roll and, in case of critical failure, the impossibility to walk again the day after.