If you want to do massive damage from a distance then forget Sneak Attack since you have to be relatively close for that.
One option is to be a Musket Master Gunslinger with 1 level of Cyclopean Seer Oracle for the Flash of Insight Revelation.
You will be too far to target touch AC but you can use Flash of Insight to roll a 20 then you just need to confirm the shot against a flat footed opponent. Assuming Gunslinger 5/Oracle 1, 20 Dex, a +1 Musket, and Deadly Aim you are dealing 1d12 +10 x4 for about 66 damage.
That is bare bones, There are plenty of things you can do to increase the damage.
If you are fine with multiple attacks then Zen Archer is a decent choice. Take Wisdom of the Flesh trait to use your Wisdom modifier for Stealth. By 6th level you should have nearly all of the ranged feats you need including Improved Precise Shot.
At higher levels you can use the gunslingers dead shot dead to make that crit huge.
My personal favorite archer build is the Half-Orc Zen Archer.
Biggest downside to the Zen Archer is the medium BAB. However they get Perfect Strike (roll twice, take the higher of the two) at first level.
Half Orcs get Scent as an alternate racial ability. Pheromone Arrows give anything with Scent a +2 to hit for something like 10 minutes after being struck by one.
So first round Perfect Strike Pheromone Arrow, then flurry with +2 with every arrow for the rest of the fight.
Toss in a Tangleshot Arrow to give them a -2 to their AC and it gets even better. Loads of arrows that go from "half of them should hit" to "Holy crap, they're all hitting!"
Half-Orc gets even better when you realize that their scarred alternate racial trait gives you a bonus to all luck based rolls, and the action point mechanics in Pathfinder are luck bonuses.
A discussion in the Master of Many Styles Monk Guide thread got me to thinking: If you can get martial weapon proficiency and Weapon Training, you can get Ace Trip(*), which will let you use a ranged weapon to trip flying creatures. You won't be a Zen Archer, but a Zen Archer can't keep flying creatures from flying away except by killing them (or at least reducing them to <0 hit points).
(*)(By the way, anyone notice that the falling damage is messed up? -- 100 feet per round should cause 1/25th of the damage of falling at 500 feet per round, not half.)