Frankly, given the way Pathfinder works, a Rogue is never vital like 2e Thieves, or even 3e Rogues were. Anyone can find any trap, and disable any mechanical one. Rogues just get a small (and not unique) bonus to it.
That said, this AP is heavier on traps than most. However, they aren't horrendously deadly or anything (oh no, 3d8+3 damage at level 14!). The Haunts are far, far worse. There ARE quite a few locked doors and chests, so you'll still want someone to grab ranks in Disable Device so you don't have to smash everything.
Given the prevalence of investigation in the AP, you will probably be happier with a Bard than a Rogue. An Archaeologist would kick butt, but even a vanilla Bard would greatly benefit from Bardic Knowledge, diplomatic skills, and Inspire Competence.
I'm running this campaign as a solo. One PC and one GMPC. An inquisitor of Calistra and a summoner. Stats were roll 4d6, drop the lowest.
We're starting part 6 tonight. No PC deaths yet. And I have not pulled punches.
The summoner has a grappler eidolon who locks down enemies and liberally uses constrict and rend. The inquisitor relies on teamwork feats, heavy hitting, and invested in Disable Device. The summoner specializes in buff spells rather than eidolon spells and is the party archer. Two PCs and a battle-pet have taken on the roles of a much larger party. It's been hard and fast but fun.
Frankly, given the way Pathfinder works, a Rogue is never vital like 2e Thieves, or even 3e Rogues were. Anyone can find any trap, and disable any mechanical one. Rogues just get a small (and not unique) bonus to it.
The traps are going to pose a problem, but anyone can find them and your party should be able to move around most of them (with some resources expended and clever thinking).
If you feel uncomfortable with that (and with possibly toning down or removing some of the traps) have your fighter go Ranger (Trapfinder) 1 / Fighter 13. He'll have full BAB progression, get trapfinding as well as a couple of weird Ranger class features.