I am currently DMing the Curse of the Crimson Throne Adventure Path and the party just hit level 4.
For several reasons, we ended up with a party of 6+DM, while the AP states to be best balanced for 4+DM.
The increased number of players led to easier encounters (especially if everybody manages to dogpile on the same enemy), with less enemies that manage to act after their morale threshold is met (e.g. this enemy runs for their life if under 15 HP) but before they get into the negatives.
I have tried, as an experiment, to raise the HP of one enemy to 225% (+50% to account for the higher damage dealt by 50% more opponents, thus leveling the expected survival time of the monster in turns, then again 50% more to account for having the opportunity to damage 50% more opponents) and still I think that the lower number of players disabled (grappled in this case) or the more frequent debuffs on the monster would have needed an even higher HP count to really produce the same level of risk and of expended resources for the party.
- The players are only getting 66.6% of the treasure they would usually get and I get told that Adventure Paths are pretty strict with how much treasure is obtainable to the PCs.
- The players have not found (once) or have not tried to gain (out of good roleplaying like not killing someone they didn't need to or just not robbing them) something like 4000 gold already, plus the equipment of a CR 4 NPC
- All the road from level 3 to level 4 has been a treasureless encounter and several plot-related XP prizes (I'm not using XP, just leveling up characters whenever the book tells me)
This led one player to wonder if I'm not being too stingy. He's worrying about not being able to tackle higher level challenge if they keep being underequipped.
Maybe 6 underequipped PCs will be as strong as 4 regular PCs, maybe they won't be able to buy needed items and I'm worried about that. Should I just give them all gold a character of their level? Should I factor the gold they should have gotten and multiply it by 150%? Keep in mind that the town the PCs are in is...
in unrest or anarchy condition, and unable to trade.
Since I don't want to spoiler the adventure, I will address @ShadowKras question about random encounters frequency in a spoiler.
The adventure has you roll a 1-in-5 chance of random encounters every night spent in town, except if the characters sleep in a costy tavern or at the Citadel. It also has you roll once per day of travel but PCs aren't travelling. So I only had to roll random encounters twice, the night they faced Gaedren Lamm (no encounter) and the night they slept at Zellara after speaking with Ileosa (a lone Zebub who I figured could have been working for Ileosa: he summoned swarms to test the PCs and then teleported away). PCs are sleeping at the Citadel since then (free food and free shelter in a safe place).
Since I'm not using XP, I have not raised the encounter chance "to get characters to the suggested level".