The people in the Keep don't even have names, so you should probably spend some time to give them some, and an evocative word or two each about their personality, goals, and appearance.
The Caves of Chaos could do with some dressing up, as they're pretty much a hack'n'slash'athon as written. Come up with some traps (maybe the orcs are accomplished with pungi sticks and booby traps), tricks (illusions are good for this...maybe the goblin chief has some Illusionist levels and has set up some illusionary dungeon features?), riddles (the mad hermit might show up at odd times while they're looting the caves and ask a riddle - help them if they answer correctly) and weird rooms (these are the Caves of Chaos - maybe there's a Magic Mouth who tells jokes, a bathtub with a water weird in it which is a friend of one of the humanoid leaders, or a door which teleports the PC who opens it to another part of the caves).
If you could weave some quests of your own around the framework of the caves and the Keep, the whole thing would get a bit more depth, too. Maybe a merchant at the Keep requires rare magical truffles, and gives the PCs pigs to root them out of forest right next to the Caves of Chaos....but the hermit covets the truffles for himself, and they have to roleplay or fight their way to a solution. Perhaps the PCs have some of their equipment stolen by a theif, and learn that there is a bounty on his head and that he lives in the Caves of Chaos with one of the humanoid tribes. Maybe the PCs learn that the Castellan of the Keep is really a doppleganger, and need to convince the other residents of this, or go on a rescue mission to retrieve the real Castellan.
In short, the Keep is easy to weave things around, but may be a little dull if run as written if you aren't easily amused by lots of combat with not much else.