Skyrim Sidelines- Rjorn’s Drum and Halldir’s Cairn: Trap or Treat

Check to the right from the doorway first- there's a trigger stone for a spiked gate trap here, but the spikes don't actually reach the floor panel and there's a considerable gap both below and around them- it's pretty easy to avoid being stabbed even if you don't leap over the panel entirely.  A couple of low-value goodies wait on the table in the corner behind the spiked gate for you, and they're otherwise unguarded, so grab them while you have the chance.

Continue down the other hallway from here and you'll come across stairs leading up a short distance- with a group of hanging-bones alarms at the top.  You can actually use these to your advantage if you're a sneaky type- the rattling will draw the two ghosts in the next area, but they won't have actually seen you, so you can use archery sneak attack to flatten them before they get too close.  Alternately, charge through and start hewing- or wait to see if they patrol into your line of sight without being summoned by the alarm (they usually don't, but the pathing in Skyrim sometimes does funny things anyways).

There's usually some light armor on the defunct table by the alarm doorway, and then you start entering the actually tomb-like area of the cave.  Advance carefully close to the bottom of the stairs and turn left before you face them- there's a draugr in one of the niches here that will jump you from behind if you're not cautious.  Take it out (and grab its stuff) and then about face to ascend more stairs.

You'll find yourself facing a throne with a draugr draped over it- this guy is a little more dangerous, but not much.  He does have a friend in one of the niches behind him, and another in a niche to the left at the top of the stairs, so take him down quickly and you'll have an easier time.  Turn back to the top of the stairs after dealing with the three draugr and you can snag a spell tome, then scavenge the burial urns to either side of the seat.