Skyrim Sidelines- Lost Valley Redoubt: And All I Got Was This Lousy Tee-Shirt

As if all this weren't enough, the wall of the ruin itself turns out to be a Word Wall, containing one of the words used in the Ethereal shout, which will temporarily make you unable to deal or take damage when used.

Make sure you've recovered, then head back onto the bridge and take the North branch off of it.  You'll spot a chest (locked, with even more loot) on the ground you can gather from between you and the tower.  The tower itself is home to yet another hagraven, who waits inside until attacked and rarely goes further than the wooden walkway on the tower's side.  Kill her however you like (an easy fight compared to what you've just been through) and then commence looting Cradle Stone Tower.

The main floor where the hagraven was doesn't have much of interest- a little alchemical paraphernelia.  The next floor up has a trap- a lightning-throwing one on the far side of the hole in the floor, triggered by a pressure plate next to the easiest spot to jump said hole.  Avoid the trap by leaping diagonally across the gap, and you can take the soulstone that powers it out, as well as swiping a coinpurse and whatever sits in the burial urn on the other side of the trap.  Leap back across and check the top of the tower for a bird's nest with an egg in it, then come back down outside and mine some more silver from the ore vein near the wooden ramp.

If you can pick the gate on the ground floor (easy), you can grab the contents of another burial urn, a couple of gear items, and then head down the stairs to get some more money out of the chest at the bottom.

Now that you've done everything else on the top floor, it's time to do the last thing here- follow the bridge out over the edge of the waterfall, to Bard's Leap Summit.  You will notice, looking down, that you're in the spot you noted earlier- the planks over the edge of the ruin above the waterfall.  The idea here is to leap from the boards and land in the water, distressing all the salmon.  If you have access to the Whirlwind Sprint shout, you can use that to launch yourself safely far, or the Ethereal Shout can be used to ensure you don't die.  If you're really brave, though, you will simply move up to the very edge and leap as far as you can- it can be done without aid!

When you emerge from the water at the bottom (assuming you went splash instead of splat), you'll find a ghost waiting for you- the Bard's Ghost.  According to him, the Summit is a famous place, although most who leap off it die.  In fact, you're the first to survive it in quite some time, and he.... well, he's the last one who -didn't-.  As a reward for your courage and daring, he trains your Speechcraft skill up one level.

That concludes Everything There Is To Do At Lost Valley Redoubt.