I consider at least the following elements to belong to the exploration phase:
- any-distance travel with possible hazards to prepare against and then avoid or face, including weather, and handling means of transportation and arranging equipment distribution
- navigation of a complex area made of different locales, either open (a city district) or close (a dungeon) in search of a target place/person/creature/object... or the exit!
- monitoring the presence of dangers, visible or hidden, including traps
- handling reduced illumination, arranging scouting and recognition
- solving riddles and puzzles, deciphering maps or any unclear message/instruction/clue
- discovering hidden/concealed locations or objects, including handling illusions
- overcoming obstacles blocking locations or objects (closed doors, difficult terrain, static hazards, chasms, perilous bridges, heights etc.)
- arranging rests/camps and guard duties