In my case both those encounters did end up involving the entire party. With the boar hunt, they all went along (and had a brief-driveby with the Sandpoint Devil on the way). And the role play with the "target" PC and Aldern was entertaining for all. With the Shopkeeper's daughter, the target PC went off on his own and the next thing the party knew, he didn't come back (he was knocked out and dumped in the alley behind the basement). They found the other daughter running the shop and tried to intimidate her (she ran out the back door) which didn't help matters. In the end, it all ended up in the Sheriff's office and the shopkeeper settled down a bit once the cathedral cleric cast a zone of truth on Shaylist and she admitted she had set the PC up. Lots of fun for everybody.
W/re to scaling, we have a party of 6 too. I've been just running the AP as written in most cases, but when granting XP I divide it by 4 and hand out a 4th to each character so that advancement progresses as expected. In some combats I increase the HP on the bosses and add a couple of extra "adds" to the fights to keep things challenging. It's worked out OK most of the time. Although often the fights I think are going to be too hard end up being a cakewalk, and the ones I thought were easy end up being really challenging. I guess as long as you have a little of both, you're good.