Obligitory spoiler warning.
I have been running Red Hand of Doom for a while. Due to various external difficulties, I have not ran as much of it as I might have expected, but I do know the first part fairly decently.
The adventure is unique in two ways. First, it is an event driven adventure. If ran as intended, things will happen if the players do not advance onward quickly enough.
Second, much of the challenge is delivered by having fights against large numbers (6-8 on average) of opponents that, while not individually impressive, go well beyond 1 hit wonder status. But, it is still balanced for a party of 4 PC's.
There are some helper NPC's made available to the party in the early going, most notably a ranger, but also a guard captain. Simply making them non combat types will go a long way towards bumping up the difficulty.
- In the first encounter, you can easily improve the encounter by putting a few more Hell Hounds in play, or subbing them out for stronger monsters. Stick to something that fits with the 9 Hells.
- Add more heads to the Hydra, and force the players to enter the swamp before starting the combat. Maybe add more heads. But beware, the Hydra fight also takes place in a swamp that can restrict movement. With reach, a swim movement, and fast healing, the Hydra can have some scary staying power, and tear apart a careless PC. There is no 5 foot step in the swamp, so anyone having to close to full adjacency will eat an AoO.
- Add 2 more Worg riders to Vraath Keep
- Customize Koth's spell list
- Advance the HD of Karkillian (the Minotaur)
- Reduce the amount of treasure within Vraath Keep.
- Advance the HD of Ozzyrandion
Other than that, you could consider making the Red Hand Forces much more active, and use some warg riders to engage in gratuitous hit and run attacks using mounted combat. This can be very effective, but as always, beware of making things more difficult for your players later on.
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