hanniball said:A good Prestige Class for a Ranger/Caster hybrid is the Evereskan Tomb Guardian. You mentioned being an Elf; which just so happens to be required for ETG.
However, you also mentioned that you are not attempting either two-weapon fighting or archery. Your only damage potential will be your spells. Not that that's a bad thing, but far more damage can be generated via sneak attack combined with your spells. Thus, I recommend the following build:
Ranger 1/Wiz 5/Rog 1/Shadow Thief of Amn 1/Arcane Trickster 10/Fatespinner 2
9th level arcane spells (CL 17), +7D6 sneak attack, good skills, impromptu sneak attack 2/day, Spin Fate and trapfinding.
How many of those PrCs are in the FRCS book? I'm not sure this build is possible given the source material limitations