As a meta-handwave, I left open a line of communication with the tavern above, where a gear provider merchant stood ready to lower any particular type of mundane gear they needed. (She had a trained crow fly down to the dungeon level with a scroll case at its leg, so the PCs can put in a shopping list request at will.) This was a case of The GM Is Being Nice Because It's Everybody's First DFRPG Adventure, and one PC mage decided he wanted to handwave some knowledge of the Earth to Air spell (and he had 1 point to spend on it) and another PC decided she wanted a knobbed club to better to brain things with.
The approach to the river had some spottable stalactite traps, visible in
this screenshot as silhouettes on the ground. Two stalactites will fall when a player walks below the
further of the two, thus threatening potentially more than one player if they were closely bunched together. I've pared it down to 3d damage instead of 10d as per the Traps section. As it played out, the barbarian was taking point, so her relatively high DR meant that she shrugged off most of the damage.
As before, the river has Leaping Leeches and some Water Serpents (downpowered Phase Serpents). I'm also including a Deep Chimera/Amphimera as shown in Pyramid 3-113 p.19, which will menace the PCs if they spend too long in the water or if they explore too close to the south end of the cavern.
As shown in the
screenshot for the northern end of the water cavern, I'm placing some shootable stalactites to block the watercourse if they spot it, which will lead to the river receding in level over a half hour or so. (Making the Leaping Leeches and Serpents less scary.) But the Amphimera will still be a potential big threat. As it turned out, the PCs noticed that the stalactites could fall, and they even used Walk on Air to lever one of them down to fall into the river, but they were too distracted by leeches and water serpents attacking the swimming party members to finish the job.
Out of the expectation that at least one PC will likely try to blast the water with lightning, I was prepared to treat such an attack as an Explosive spell centered on the hex which she shoots, potentially doing lots of damage to the Leeches and Serpents - although the Amphimera has an Immunity (Electricity) since it uses electric shocks itself. As it turned out, the PCs did not use lightning after all, perhaps because one PC went into the water early on.
To the south end of the cavern, the main draw is on one side with
an opulent tomb entry way with another "Leave My Land" rune high on the crosspiece. But for those PCs who can fend off or avoid the Amphimera, I've put a little
bonus niche around the river on the other side as a reward: a little Speleid (GURPS Underground) rock nymph makes her grotto there, and if they offer a gem as a sacrifice, she can give them an oil which has various combat bonus effects against rock beings. The exact power will depend on the color of the gem, and can include: DR divisor if smeared on a blade, DR elimination for a few rounds if used as part of any missile spell, and a grenade-like attack with the oil to convert stone into a muddy mire (slowing the enemy).
These oils lose their potency after being removed from the cave.
The PCs did not trigger the Amphimera, and did not follow the eastern side of the cave wall around to the Speleid's grotto, so they ended up at
the entry way to the dwarven tomb. There was a tile grid on the ground, as well as two patrolling Stone Golems who seemed uninterested in bothering the PCs, although once they approached the grid, the Stone Golems walked away and stood flanking the tomb door entrance, as if expectant.
Hmm...
tiles, you say? Smells like a puzzle. Looks like this GM is a fan of contrived dungeon pattern recognition tests!, etc. The solution to this came about from a dwarven drinking song (performed by the GM without the aid of alcohol) at the start of the adventure when the players were at the tavern.