Warren the halfling, HP 30/33, AC 23
(Heading around south and then over to check the door of the tiny building first. Only going around to the keep itself after checking out that little building. If there's something in that tiny building, Warren will sneak off to inform the group and let them know to avoid it for now, so that they can still make their attack on the inner keep with the advantage of surprise.
After the little building in the southeast has been checked, Warren will continue around south and up to the hole in the main wall at L-19, keeping a careful eye on the giant skeleton half-buried there, ready to jump back outside if it starts moving while he's walking over it.
He'll check the little building's door for traps and locks first, and pick any locks if needed, to check inside as quietly as he can. Listening at the door first, of course, before he goes fiddling with it at all. Then slowly taking a look inside, without opening the door all the way, to see if anything dangerous is inside. If there is something dangerous-seeming inside, Warren will judge whether or not it's something he can eliminate with a little invisible backstabbing, before deciding what to do. If he sees no such thing, then he'll move away from the small building and head around to the hole in the keep's main wall.
Then walk carefully over the rubble and take a good look around that section of the courtyard, including a careful look inside the left-side building (the southwest one) through the hole in its wall, without going inside. If he sees nothing in that southwest building, he'll creep inside the entrance of it to take a better look, listening all the while for signs of danger or movement.
Assuming Warren sees and hears nothing dangerous inside the southwest building, he'll go listen at the door of the southeast building in the keep, then return the way he came, going back outside the keep. At that point he'll climb the southern wall until he's at the top, then toss a pebble off to the side of the group to signal them.
Once they start approaching, Warren will climb down to the thatched roof of the southeastern building in the keep and ready himself to jump down to it and break through (only jumping down once the rest of the group is about to reach the door). If the roof doesn't give under his weight where he jumps, Warren will head over to one of the smoke-holes, jump down, grab hold of the edge, and swing in to the side, so as not to land on any firepits or whatnot.
Warren's possibly-relevant skill bonuses for these actions are..... Balance +11, Climb +5, Disable Device +12, Hide +16, Jump +10, Listen +10, Move Silently +14, Open Locks +14, Search +10, Spot +8, and Tumble +12. Larian's invisibility spell will add another +20 or +40 I think to the Hide checks, depending on whether or not Warren's moving at any given time.
He will be taking 10 on any checks that he can, but if taking 10 on Climb doesn't get him partway up the wall on the first try, then roll further Climb checks normally. Naturally, if he falls he'll try Tumbling to lessen the impact. If he can take 20 on the Search or Open Locks checks, then he will (I can't recall off the top of my head if he can or not). Warren will be checking for traps at the hole in the south wall and at the tiny building's door.
Warren's carrying all of his own gear once again, and with it his total weight is approximately 55 pounds. He will have his short sword drawn the hole time, except when climbing, disarming traps, or picking locks, and will draw the short sword again after each of those actions, like just before he jumps down to the roof. For reference again, his readied maneuvers are Burning Blade, Mighty Throw, Cloak of Deception, Shadow Blade Technique, and Stone Bones.)