For my Fortress of Tears game, I envisioned it being very much a LotR-clone, right down to the long marches overland. The characters are HERE, the monsters have the travelers checks HERE, kind of thing. To that end, I came up with a very detailed set of travel rules, with hex-by-hex turns that had Survival checks by the designated Guide to avoid becoming Lost, Perception checks by the Scout to avoid unwanted encounters, Perform checks by the Marshal to keep up morale and help avoid Fatigue, modifiers for terrain, weather, etc.
Then, looking at the (mostly) finished project, I just sorta blinked a few times and said, “What were you THINKING???”
It was a very playable system, and did a good job of simulating fantasy-overland-travel of the type likely to happen in a “war against the dark lord” sort of campaign, but when I was suddenly confronted with the question of “How does this actually make the game any more fun?” I couldn’t find a good answer.
Thing is, I can imagine once upon a time looking over a system like this and going “Cooooool.” Because why wouldn’t you have a detailed system for this? That’s what games have, is systems. That’s how your world and the characters’ world interact. You can’t just decide what happens, that’s cheating! But if I’m honest with myself, I can then just as easily imagine myself using the system for all of three “turns” and deciding it’s way too much work, throwing out any result that doesn’t interest me.
At the end of the day, I ended up with a slightly-modified version of the standard Pathfinder rules, which do little more than give you rough MPH measurements with some modifications for terrain and guidelines for fatigue if you push it. It’s not particularly nifty or cool in any way, but it does provide a reasonably fast framework for figuring out how long it takes to get from !The Shire to !Mordor by way of !Rivendell. Since any encounters that happen are only going to be ones that I think are “interesting” anyway, I might as well just spend my time coming up with those instead of wasting my time trying to simulate the boring bits on the off-chance that characters might come to an encounter lost or fatigued.
I don’t know what it is about the gamer mindset, that occasionally gets fixated on the rules as an end to themselves. Maybe it’s just a geek thing. But to paraphrase uber-geek E.G. Gygax, “A good GM often only rolls the dice to hear the noise they make.” A well-run game is all about the players and the story, not the mathematical construct that it rides on.