Dungeons are just spaces like forests and the streets of Neverwinter, encounters occur in these spaces on a regular basis depending on the location which varies greatly.

For example, moving on the high road during the day there is a 1 in 20 chance per hour to have something happen and that something can include an encounter of various severities. It increases on a tributary road and changes for off-road. Say on road, you have a chance of being ambushed which can be tricky even if you're wary and watching. If you're in the forest you won't be ambushed, as no one expects you to be there, but you could be stalked or stumbled upon by something and that's roughly the same chance but has varying consequences and scenarios.

So resting just off the road vs resting in an open field is about the same chance of danger. Resting in a hidden location in the forest is 50% less dangerous (1 in 30 per hour).

Moving off-road with stealth is 50% less dangerous.
Moving while covering your trail will prevent stalking
Moving slowly is similar to stealth but will take longer and therefore increase the number of rolls per mile traveled, you must be proficient in stealth to move with stealth and cover your trail otherwise you just move with stealth.

The math is set to favor moving with stealth while covering your trail but while moving slowly decreases the encounters per hour it is a wash for encounters per mile. Without proficiency, moving with stealth is about the same as moving slowly and the speed is similar as well if you have proficiency your speed can be normal with stealth and counter-tracking.

Camp fires will ward against creatures but draw bandits to you so it will change the encounter type but it will also dramatically increase the danger of bandit attack if they're in the area because of the light, smoke, smell etc. Intelligent and tame creatures typically are drawn to the fire, wild creatures are discouraged.

Dungeons:
For every level down (roughly) the danger increases by 1/20th.