135 xp divided into four, at least that's how I do it. Many just level the characters when it's time for leveling.
Okay, the XP chart can be found Here.
Give them the Individual XP chart 1-3.
Give everyone an equal share of XP.
Giving differnt levels of XP can be confusing and disruptive to the game.
Although Rise of The Runelords is a hard AP you might want to find another player.
Alternatively, you can just level your players when the book mentions they should have leveled.
If you have the Anniversary Edition this is listen on page 11.
+1 for adding an additional player if at all possible. Some points in the AP are especially deadly.
To follow up and clarify.
If the monster is worth 135 XP, then that is the total XP the GROUP gets. Every member gets an equal share; it does not matter who actually landed the killing blow. Since your group currently has THREE characters, divide 135 by 3 (NOT by 4 as was previously suggested in error) to get the individual XP, so each group member (rogue, druid, and Seoni) gets 45 XP (the wolf gets nothing).
Thanks for the answers. I think I go with the suggestion to just level up the characters when the book says they should.
I can add another NPC to the group. What class would you suggest it would be? So far we have a Druid, a Rouge and a Sorcerer. I would hate for the players just to manage half the AP. I paid lots of money for this and I wanna see it all the way through :)
Well, you need a healer, and you need a formidable front liner. Maybe bring in a Hospitaler? (Paladin healer archetype) Rogues tend to get squished easily, and healers tend to draw enemy fire, so that could help your players have fun.
About the four-error from earlier: I thought of it as three players+GMPC.
*very ashamed*
Listen to DM_Blake!
You could also simply dispense with XP altogether. XP is nothing more than a pacing mechanism, to say 'you should go through X encounters before levelling up'. Since you're doing an AP, there will be points where the book will say 'The PCs should be X level before continuing' ... just level them up when you hit one of those spots.
Exp is almost always shared between the party.
There are notable exceptions like when players who perform quests by themselves, role play really well, defeat enemies solo or other conditions where you might award one specific player exp.