Skyrim Sidelines- Red Eagle's Sword: The Eagle's Stair

Be careful at the top of the first set of stairs- a pressure plate in the floor right in the middle of the landing will trigger a hail of poisoned arrows.  This can work for you, against you, or (most likely) both.  There are more stairs to go further up from here, culminating in a stone platform with an altar on it and wooden post-stairs leading still further up.

Check under the wooden stair for a large stamina potion and a low-value unlocked chest, then check the altar as well to scoop up a large magicka potion and possibly a semi-useful bow.

The wooden stairs bring you into a small underground ruin, with a single corridor.  Head straight for the crumbled far end of this to snag several patches of mushrooms and yet another coin purse, then head up the stairs that are the side-hallway to reach the iron door leading to Red Eagle Redoubt.

Red Eagle Redoubt is a largely vertical exterior 'dungeon' of fairly little complexity- the core of it is a series of stone staircases leading continually up the mountain.  The initial door spills out into a camp that forms the lowest part of the location, with a stack of firewood and a large bonfire.  From your entrance you can cross this area (while likely under fire from the Forsworn archers above) and look under the huge fallen pillar for a rarely-spotted bag of coins.

At the first landing you'll want to head left to kill the first archer you find here, then look to the other side of the landing to find an odd wrap-around area that leads to the overhead of your 'entrance' door.  A locked chest here gives you a chance at a fair amount of valuables, but you should probably leave it be for now, as the next landing's archer is liable to already be flinging arrows at you.  If you have excellent sneaking skills, though, you can simply pick off the archers one by one as you see their heads over the stairways each time you near a landing- light-footed characters have their usual easy time at an outdoor 'dungeon' when they're here.