You're in trouble already the moment you land (on the corpse of an unfortunate Breton man): the room that the pit opened up holds a pair of draugr wights and a restless draugr, ready to fill you with steel and arrows. Just to make things worse, the double-door entrance to the room opens on a haul where an additional draugr is patrolling (though this one is thankfully not anything special). The fight here is tough in a cramped, dark room and will likely eat through some of your adventuring supplies immediately.
Deal with the battle however you can before looting the corpses and the burial urns, then step out into the hallway. Face down or ambush the draugr there if you haven't already fought it, then make your way along to the turn.
A handy potion and another urn await you here in the corner, and then you can have a look at the next room, which holds a lever surrounded by candles as though it were waiting for its lover or somesuch.
Make note of the additional levers on the sides of the room as you take a right to pluck some coin off of a draugr corpse, as these are part of getting out of here. The central lever, after all, is a trap rigged to fill any who pull it with poisoned darts. Carefully avoid that central area, instead using the levers on the sides to open the porticullis and reach the stairs that lead up into the rest of this dungeon.
The short hallway at the top of the stairs includes a pressure plate that you direly want to avoid if you work by surprise at all- it opens the door automatically, alerting and releasing several draugr wight guards, and rams a spear through the area overhead of the pressure plate as well. If you're canny, you can use the rock to play peek-a-boo with the draugr, who won't often think to look through the door. This is helped by the fact that hte plate will close the door as well as opening it- archers can have a bit of amusement here, as can skilled sneaks and some spellcasters (open-atronach-close). Everyone else should just charge through at top speed so as not to get stabbed in the head by the spear trap.
With the guardians dead, toss the room for some valuables, a few books, and a fistful of remarkably well-preserved alchemical ingredients. Once you've scoured the place for everything of value, it's time to open the door opposite the stairwell.
