My group the other night played City of Golden Death, a L5 module, for PFS. After a near-wipe, we retreated and called it game as we didn't think we had the firepower to finish the final series of battles.
The problem we encountered is that the module assumes you will be leveling up as the game progresses and PFS only allows leveling post-scenario.
Before entering the Third Ring, the PCs should all be at least 6th level. If they are not, use the Xin-Grafar Random Encounters table on page 17 to give them enough experience to reach 6th level. As this is the climax of the Price of Immortality adventure trilogy, the encounters in the Third Ring are quite difficult.
If you don't have a level appropriate character, 4-6 in this case, you would get a PFS pregen at L4. We'll assume any PCs are L5. When you get to the final series of encounters (CR 7 Undead Dragon, CR 8 Dark Naga, then a fully buffed CR 8 caster), you could be in for PC deaths or TPKs, no?
As someone looking to GM, how do you handle modules (based on characters leveling in game) in PFS play knowing that a party of APL (module level+1) would probably walk over the beginning 2/3rds of the adventure but a party of APL (mod level +0/-1) would likely not be able to finish it? What strategies have you discovered or employed?
Kleenex is helpful, but character sheets are fairly tear-absorbent. I also encourage players to write angry e-mails to Mike Brock before they have a chance to calm down.
Seriously, this danger is present in any Pathfinder module adapted for PFS. For every group you have who gets wiped out or retreats, another group will insist the module was a pushover. I wouldn't expect any action to be taken by the campaign. Just make sure that you stress to your players that the adventure is very tough at the end and they shouldn't hold back if they want to complete it. Encourage them to purchase lots of disposables and use them liberally.
I'm being only slightly preachy when I say that experience will teach you not to make assumptions about your players and their expectations. It seems like every time I tell players that an adventure is very tough and I expect them not to complete it, they plow through everything. When I tell players that the adventure is weak and I doubt they'll feel challenged, it turns into a bloodbath and they're all like 'What the Hell, Doug?!".