Personal choice. As for myself.
From level 1 to 25, I will clear catacombs in hopes of maps, if I fall in a Trap Door I will remake catacomb and not bother clearing (oh, small note: if you spawn monsters and remake cata without killing them, you will not gain any Prof points from the first wave of monsters respawned in new catacomb, you have to kill them off first.).
If I am lucky with catacombs at a higher level to clear, I will try to clear it, otherwise I will remake catacomb is spun to a location that is back at the beginning. Note: if it is not too far, I would use /set easy 1 to minimize monster spawns and then /set easy 0 for unexplored areas.
I never use whistle, and if I have 0 whites and find a well, I will use arrow keys to spin on the spot, not whistle, I prefer different level monster spawns compared to set level monsters.
Haven't done maps for awhile, but I use to use them at certain levels hunting whites or items.
Ooooo walking around spawns higher leveled monsters? Do you know the possible range of those monsters? I didn't know that