The ones staying behind will be hidden and not making any moves to engage or reveal their presence. Just to observe only. But if everyone wants to head back and then come back that is ok too as there is always strength in numbers.
Rethal, you are the expert out here: If you can find a place where you can observe the caves with little fear of detection, then use it. The more we can know about our foe, the better. If you want a companion, so you can take a break while continuing to observe, choose one.
The others will return to the keep and buy adventuring supplies. If they can find a thief to manage traps, that would be good too! Then they return here.
Rethal will climb a tree where he can be up in the branches and hidden but still be able to see most of the activity around the caves. He will tell the others to go ahead and head back to get the supplies while he observes. He will let you know what he sees.
Oberon, Aseneth, and Gervase are able to make it back to the keep without incident. When they arrive, a new caravan has just pulled into the area bringing with it a handful of adventuring types who head straight for the One Eyed Cat.
Meanwhile, back at the tree. As Rethal sits in his tree, he sees some rustling in a copse of trees almost directly across from the cave they first inspected. Out of the trees and brush he sees a troll carrying an empty barrel walk over to the stream running through the ravine. As the troll gets ready to lower his barrel into the water he stops, puts his nose into the air and starts sniffing. He slowly turns in Rethal's direction. After about a minute of this, he goes back to filling his barrel with water. Then he stands up, takes one more sniff in Rethal's direction, and heads back into the copse of trees.
We should be as quick as possible, so we don't leave Rethal long. I suggest we split up - you and Aseneth head to the One-Eyed Cat and see if you can recruit a thief and any others to our cause. I'll get the shopping done and meet you in the tavern after. Or we can do the opposite if you prefer.
Assuming no objections, Gervase heads into the general store to but the following, pointing out that its a big order, that he's risked life and limb to bring arms to the keep, and everything else he can think of to try to get a good price.
50ft hemp rope 1gp 20lb
10 iron spikes/pitons 3sp 5lb
Small hammer 1gp 3lb
Quarterstaff/pole - 4lb
Fishing hook 1sp -
50ft fishing line (Silk) 1gp 1
1 Crowbar 2gp 5lb
TOTAL 4gp, 4sp ? 37lbs
He'll then head to the One-Eyed Cat to see how Oberon is getting on.
Out of Character: If Oberon would prefer to shop, he'll head straight to the tavern and ask Wilf the Barkeep's advice on recruiting a trap-finder/lockbreaker (Gervase won't use the T word)
Oberon will offer to do the shopping, know that talking to people is not his strong suit. To the list he will add half a dozen waterskins and 10 man-days of iron rations to the list in case we get trapped in the caves.
Oberon is able to gather all of the supplies he's looking for at the Trader's shop.
When he joins Gervase in the tavern, he finds that there are a few adventurer types hanging around, waiting for their next job to come along, but none that appear to be the 'scouting' type.
As he joins Gervase, the serving girl appears seamimngly out of nowhere and asks, "Can I get you something for lunch?"