If your #1 goal is SURVIVAL, play a cleric or druid. They are hands down the easiest class to make into solid, surviveable, extremely potent beat-stick wielding tanks.
Imagine this:
Rogue 1/Cloistered Cleric (Trickery domain) 9
Feats - Crossbow Sniper, PBS, Precise Shot, Rapid Shot, Rapid Reload (Taking Able Sniper next)
You buff with Divine Favor, granting +3 to hit and +3 damage (just as good as a SA die) and Cat's Grace (gained via a domain), granting +2 to hit and +1 damage. Divine Insight grants a +14 bonus to Hide checks, so its easy to pick up your SA damage. Your saves are great, with the doubly vitally Fort and Will saves taken care of.
If you get into melee, whip off a Divine Power and you're good to go.
Your skills are still great, and you have trapfinding, which lets you detect traps. Just purchase Search/Disable Device cross class if need be, or drop into Church Inquisitor (has Search as an in-class skill).
Oh, and you're nearly a full-casting cleric, can drive away or command the undead, and have a spell for nearly every situaiton.
THAT's how I'd build a surviveable stealthy skill based ranged warrior in a game where TPK fear is a big deal. If you don't want to be labeled as the "healer," just don't advertise that you're a cleric, or be neutral/evil and rebuke undead so that you can't spontaneously convert spells to cures.
A less "extreme" version would be Rogue 4/Cloistered Cleric 4/Assassin 2. I would try to squeeze in Practiced Spellcaster (to fuel Divine Favor and other handy buffs) and pick up more wands/scrolls in that case. Note that the even levels give you better BAB and saves than odd levels usually do. For example, the above build has Fort +5, Ref +8, and Will +5, along with BAB +6. Not too shabby.