I love Opportune Parry & Riposte. That is the only reason I don't really like the Picaroon (that being said, if you can dip into another class which'll grant you Parry & Riposte...)
Taking Swashbuckler and Pistolero together, then using a Sword-Cane Pistol and a Musket, I can see some serious hilarity happening, especially once you get to lv4 in both.
Flying Blade is literally designed for throwing knives, though - I'd suggest using that over wasting the Musketeer archetype on throwing knives.
I've been doing a lot of thinking between the Musketeer and the Picaroon, the ACG is very particular on how the set ups are for all the classes, mainly due to its balancing act.
The Musketeer has a lot of essencial things you'd need for making a Gunslinger, thats why its a good crunch for a 1 level dip, but because the Swashbuckler concentrates itself around using a melee weapon, all of your upcoming class features will have nothing to do with your gun. The Picaroon on the other hand gives you plently of more resources as you progress through levels for only using a pistol with your sword, without the gunsmithing, however with more options for both parties. So it all really depends on what you're trying to go for. Theres a lot of other things I'm not mentioning about the two, but I'm just trying to give you the basic idea. Personally, I'd go for the Picaroon, because it has a lot more to offer, and a sword and a pistol...C'mon, how cool is that? :)
If you're still not sure about the Picaroon, dipping 2 to/or 4 levels in Steel Hound Invesitgator wouldn't hurt, you'd get Inspiration as well as Panache, Gunsmithing as well as a battered Gun, and the only two talents you need to worry about are Extra Grit and Rapid Reload if Expanded Inspiriraton and Underground Inspiration aren't your cup of tea, plus you get can make alchemical cartridges. Hope that helps.