Backporting for 3.5?

[Tinalles]

I'm in two groups. In one, I'm GM'ing Haunting of Harrowstone right now, using the ordinary Pathfinder rules.

My OTHER group, in which I'm scheduled for a rotation as GM, has expressed interest in running it too. This would be helpful, since running the same thing for two groups is less prep work than running two completely separate campaigns.

The problem is that group 2 wants to keep using 3.5 rules. Also, group 2 is quite large, with SEVEN players.

So, how much work would it be to backport Carrion Crown modules to 3.5? The Haunt mechanics are pretty closely tied to the PF cleric's Channel Energy ability, which 3.5 doesn't have, so that would be awkward.

Also, how would you go about adjusting the encounters for such a large group? The PF rules are already slightly more powerful than corresponding 3.5 ones. Should leave them alone, or increase the CR by 1 or 2 because there are just so many PCs?

Or maybe it would be best to invest in a 3.5 era Pathfinder AP ...

[TriOmegaZero]

Use them as is.

[Kyonko]

Stress the importance of holy water and the siphons, make sure that the party is extremely well aware of the Ouija board. Otherwise just as TriOmegaZero has said, you can use the module as is. If you feel that the PCs aren't getting challenged during the game, there should be a thread here for boosting the difficulty of the entire AP.

[CuttinCurt]

Let them play 3.5 if they want. You just keep on using PF as written. They are compatable.

[sozin]

If I were GMing, I'd be loathe to run the same campaign twice (with different rulesets, no less) ... I'd be bored. Run Runelords, or Legacy of Fire!

7 people is a lot - good luck. Don't let any of them be summoners or summoning focused casters, your combats will take forever!