the players don't know exactly where the dungeon is; and

What's the nature of the dungeon? Is it a natural cave? Old buried catacombs? Bunker?
We need to know how the entrance looks like.

>>54800803
is a temple to a snake god, now in ruins

>>54800505
Sounds like it's just a larger dungeon with the first level being a surface battlefield.

>>54802218
https://1d4chan.org/wiki/Five_Room_Dungeon

puzzle: finding the dungeon
guardians: random wights on the battlefield
setback: the dungeon is in fact deeper than they thought, they need a boat to sail an underground lake
combat: the snake couple, hatching eggs
reveal: the hero that put the sword there is actually there; undead, animated by a swarm of maggots

>>54800505
>>54801926
I would say to have the crumbled walls of the old temple above ground, running that as a sort of mini-dungeon where they have to fight of ghosts and identify the old purpose of the rooms to find the stairs down.

>>54800505
There's twice as many snake statues around the battlefield as PCs, they have to find the real ones (half of them) and destroy them. Destroying a fake one summons enemies.

>>54800505
The battlefield itself is within the domain of noble family whose ancestor committed several deeds of renown during the battle and see it as a point of pride/memorial, as such the family employs armed men to patrol the roads and paths leading to the field to discourage looters. Upon discovering the party attempting to access the battlefield with permission, the patrolmen will attempt to apprehend them; should a fight break out, one of the patrolmen will always leave the area to inform the rest of the guards as to what is happening.

Accessing the battlefield at night makes it easier to avoid the patrols, but your party runs the risk of encountering looters. Fighting them increases the chances of the guards discovering you and freshly spilled blood might awaken the restless dead.

The battlefield is haunted, except when it's not. Some say malign beasts roam the field on the new moon, others say the full moon sees ghosts and corpses rise to reenact their doom, and some speak of seeing fiendish creatures dancing deliriously around blasphemous rituals on the solstice. Gary's cousin Lester, you know Gary from the pub - tall guy with a gimp leg, says he saw a dog as big as a horse with bleeding eyes and a fire in his mouth last Tuesday.

File: 1456525072758.jpg (668KB, 1200x1200px) Image search: [Google]

668KB, 1200x1200px

>>54800505

Make the center of the battlefield a burned out town, that was at some point fortified and eventually overrun during a siege. The old walls and battlements become a sorts of maze. Have the players navigate the maze to find the entrance to the dungeon. Navigate through houses and over roofs, lots of crannies for hiding and sneaking, splash damage changes the terrain a little, makeshift walls and dead ends, hidden rooms filled with ghouls, urban fantasy shit. Focus less on finding the entrance and more on surviving the journey.

Bonus: Traps were left behind by the defenders of the town to frustrate the attackers.

I like your dwarf fort. That's a cool dungeon