Short version of above. My suggestion is:

Short Rest

- No longer hard limited to 2 (either 4 or unlimited)
- Instead, discouraged by food cost. Maybe 10 Camp Supplies per Short Rest.
- Random Encounters may occur during Short Rest. The more dangerous the area, the greater the chance. Maybe 1-10% chance, 10% being hostile, alert goblin camp kind of thing.

Long Rest

- Must unlock location first (such as in Underdark)
- Discouraged by food cost. Maybe 10 times Short Rest Cost
- Random Encounters may occur. 10 times the chance of encounter as Short Rest. So, if 2% chance for Short Rest, it's a 20% chance for Long. Closing doors or finding hiding places reduces chance.

Give characters the ability to make Survival checks to forage or hunt for food. Ranger would then benefit from Favored Terrain.