If you're going for flexibility, consider a rogue. At 15th level with maxed out UMD and a judicious selection of items, this class could be a killer in and out of combat.
archer builds of any kind generally work when you have a meat shield or you know you can pick off the opponents from a distance.
If you are going to be on your own, I wouldn't expect that you can keep the other PCs at a distance for very long before they want to close in the distance ... hence, a concept relying on archery may not be the best choice
(I don't think that made as much sense as it could -- it's late here and I'm sleepy... sorry if it isn't clear )
Well, I went with the cleric archer, though I seemed to use far more of my spells than my bow. It was basically a series of combats, with a couple of battle royales and some 2 on 2 as well. The only time I had any trouble was when I was grappled by the druid shifter. I had some power word spells I could have used (from war domain), but he was a construct and so I knew they wouldn't work on him. Otherwise, the combination of a harm spell here and a summon monster viii spell there proved very deadly. In the end I came out victorious. I won a tropy that had "1st Annual Nerd Rumble" on it. The others got a choice of three sets of dice, and they picked in order of who came in 2nd, 3rd or 4th. In all, it was a fun night, though I am looking forward to getting back to our regular campaign with my ascetic monk.