I guess though it depends on what a 'random ecounter' is here - on one extreme it could be a dozen wandering monsters who all attack the PCs, on the other hand it could be mostly weather, terrain obstacles, exotic phenomena, friendly or neutral NPCs, game animals, and such, with very few monster attacks.
I try to keep the attacking monster encounters to no more than half the list of potential wilderness "encounters".
My wilderness random charts include environmental obstacles and hazards:
A river that will require a lot of effort to cross, else will require an extra day's travel time to go up/down and find a fording.
Everyone has to make a Fort save or get a disease. (Come up with a reason -- bug bites, bad spore cloud, gods hate you, whatever.)
Someone/thing stepped in a snake nest. Take 1-10 venomous snake attacks.
Bad weather. Depends on the climate.
Animal trap.
An old bridge is collapsing. (It may collapse under the 1d6th person crossing, or it may already be broken and require repair before anyone can cross.)
I try to have all encounters/events actually have some game effect, not just be window dressing.
It's actually pretty hard to come up with a long list of environmental hazards for each terrain type, but every time I do think of another hazard, I add it to the list and add a potential fight encounter (to keep things about 50/50).
And "monster" encounters include knight patrols, elf hunting parties, halfling trackers, etc. Creatures that may confront the PCs, but aren't necessarily enemies. And even some encounters with enemies might not turn into a fight -- the PCs may wisely avoid an encounter with a wandering giant party, or a small wandering party of goblins may try to avoid the heavily armed PCs. It's fun both ways -- watching the PCs swallow their pride to avoid something tougher than them, and watching the PCs smile smugly at watching the weaker party flee from their approach.
I've been using this kind of thing since my AD&D1 days. In fact, most of my current charts were just expansions of those older charts. There are some parts of the campaign world where it's low likelihood of encountering any kind of battle situation, and then there are some parts of the campaign world where the wilderness is nothing but survival of the fittest.
All this lets the PCs use their abilities for things outside of dungeon crawling combats. Plus, it lets PCs use things like flight and teleport for something outside of just tactical strikes.
There was one campaign where the PCs were on a mission that, (unknown to the PCs), some gods considered worthy of their attention. When the PCs were about to embark on a dangerous leg of their journey, into a wilderness area they didn't know, they hired a guide. After a week's travel, led by the guide, with no encounters (fights or obstacles), the group grew suspicious that something weird was happening. (I was rolling as normal, but nothing happened.)
When they reached their destination, (a lost city in the wilderness), their guide took his payment and then left the group to make his way back, alone. The PCs (and Players) were dumbfounded. After the campaign ended, one of the Players asked about that guide, and I let them in on the secret: it was Farlanghan, himself. He did nothing to help them other than insure they got to their destination without problem.
Bullgrit
