Let's try to constrain the variables as much as possible we'll talk about an unencumbered human walking outside of combat. (the whole indoors/outdoors seems an artifact of wargaming to me and I'm going to ignore it, last I checked I walk the same pace indoors and out).
Average human walking speed is a little less than 3 mph. Jogging is somewhere around 6 mph-- once you get around 8 mph people consider it running. And what about the top end? world record sprinting would be in the 23 mph range, with short bursts higher than that.
That works out pretty nicely; if we aren't too worried about realism we can say there are four movement rates that double in speed at each step:
- walk 3 mph
- jog 6 mph
- run 12 mph
- sprint 24 mph
Okay, so lets see how the latter approach might work:
- walk 2 mph
- jog 4 mph
- run 8 mph
- sprint 16 mph
Let's look at 1. How long can these rates be sustained?
Sprinters can sustain speeds near 20 mph for 40 -50 seconds. So, if you consider a combat round 30 seconds, a character should be able to sprint for one round. That's easy to remember and elegant. Unfortunately, I tend to think of my combat rounds as 10 seconds-- 30 seems incredibly long for a brutal, non-ceremonial fight. Hmm, do I say players can sprint 5 rounds? I'll have to think about that.
How about the other speeds? We're calculating very roughly here, but I think the next tier of speed would be the 5000 and 10, 000 meter races. There you have people sustaining a pace of 16 mph and 14 mph for 12 and 26 minutes respectively. I'm going to go with that 12 minute mark and say it is closer to a turn. So, our characters can run for 10 minutes.
After that it gets less critical, people have sustained speeds of 6 mph on a treadmill for 24 hours. And it's probably less likely that such careful measurement will be required outside of combat. Average US marathoners maintain ~6 mph for 4.5 hours. We could say a jogging pace could be sustained for somewhere between 2-5 hours. I don't have a clear preference pulling me on this.
The walk pace can be kept up as long as you go without sleep. I'm no athlete and I've done 27 miles in a day that included going up and down Mount Whitney. So, yeah, characters should probably be able to do 30 miles a day without pushing too much , which equals 3 mph for 10 hours.
That's at least some rules of thumb. How about answer 2. from above. How far can you move in a combat round? Going with our second speeds above and assuming a tabletop inch equals 10 game feet, and also assuming my 10 second round (man this is feeling like the SAT or something) characters can:
- walk 3 in
- jog 6 in
- run 12 in
- sprint 24 in