Wilderness rules, a wishlist

I'm looking for a good set of wilderness travel rules.  The setting of Signs in the Wilderness is a wide, poorly-explored country, where settlements are rare and scattered.  Travel itself is the framework for adventure.

William Manly, Andy Thomas

So far I've been using homebrew, hacked-up versions of other games' rules.  For many years my usual group had some mix of AD&D 1e/2e rules, using whatever seemed to work well enough.  For the last game I ran, we used a homebrew set of PbtA-style moves for overland journeys, and it worked surprisingly well.  (Some rulesets, like the one from Avalon Hill's Outdoor Survival, I would be less likely to recommend.)

So what would a perfect set of wilderness travel rules look like?  They would:

1. cover the most typical situations for this genre of adventure,
2. yet be flexible or general enough to apply to unexpected situations as needed,
3. and not take too much time, brainpower, or paper.

Tough Decision, Jim Killen

There's a long list of situations that I'd love to see covered.  I imagine a ruleset that handles all of them would turn out to be far too cumbersome, with page after page of tables, endless die rolls and modifiers, and no one would really know the rules that well.  But if I could have it my way, the rules would be great for:

Travel itself

Start with a day's travel:

• How far do you get?
• Do you get lost?
• Do you get hurt/cold/sick/exhausted?  Does your morale drop?
• How much food/water do you consume?

For each of those, a few conditions should matter:

• How are you traveling (on foot, by canoe, etc.)?
• What kind of terrain are you traveling through?
• What's the weather like?  (Getting lost in fog, drinking lots of water in the hot sun, etc.)
• How much are you carrying?
• How sick/injured are you?

Dealing with obstacles

I'd like rules for obstacles to be general purpose, but there's one particular obstacle that seems to show up all the time in this genre: crossing a creek.  It presents a few particular dangers:

• getting your powder wet
• losing your gear and having to search downstream
• being swept away yourself to be buffeted against rocks
• getting soaked from head to toe in winter and dying of cold

I'd like to see the party struggle with the decision to cross now, as quickly as they can, or spend hours searching for a safer place to cross while losing valuable time.

There are other kinds of obstacles (portaging canoes, climbing a cliff, spelunking) so I'd enjoy seeing a general rule for crossing an obstacle to movement, but at the same time I appreciate having some of the consequences of danger spelled out for the GM.

Doing things along the way 

• foraging for food/water
• noticing things along the way: animal activity, smoke from distant campfires 
• tracking, following a trail of footprints and other signs
• trying to cover your own tracks as you go
• setting an ambush, lying in wait
• noticing an ambush before it's sprung on you

Again, terrain and weather matter.  It's easy to follow footprints in the snow, but if it starts snowing again they'll be covered up quickly.

Making camp

• rest, recovering health/morale, based on how good the camp conditions are
• who/what notices your encampment, based on how well concealed it is, fire, noise, etc.
• keeping watch, looking out for danger at night

Lewis and Clark, Mort Kunstler

Some of what I'm looking for is rules: concrete ways to decide what happens, to give the hard decisions to the dice and the tables, not the GM.

The other part I'm looking for is inspiration: ideas and suggestions to help describe this genre of adventure.  When running a game, a list of possible results is often handy, not as a way to constrain what the GM does, but as suggestions and inspiration.