I'm hoping to get a couple of suggestions on putting together a Riftwalker/Nar Demonbinder/Ultimate Magus caster level focused build. The Riftwalker is a 10 level class granting up to eighth level spells, and abilities largely involving sensing rifts and teleportation. Neither class gives much of a spell list, and the combination is Int/Cha MAD, but there is a bit of intentional hamstringing in play. The character will be largely in the background, contributing summoning/planar ally, party transport, and the occasional inimical Blasphemy. I'm not planning on making much use of the Riftwalker class abilities, and would be cool with prestiging out after a single level.
The entry requirements are a little weird, but the class can be entered at 4th level without early entry, or 3rd with.
Skills: Knowledge (the planes) 5 ranks, Search 5 ranks, Spot 5 ranks, Survival 5 ranks
Spellcasting: Ability to cast 2nd-level spells or use ki strike (magic)
There isn't much in the way of single class entry, that I can see. A UA generic spellcaster works, for one, but I was hoping to avoid that. My current thought is to use Master Spellthief paired with a level of Planar Ranger on a human with 16 Int (necessary to get several cross class skills). Please note that for the purposes of the game in which this character will participate the feat Precocious Apprentice is considered to allow early entry. I'm writing this with the initial assumption of flaws and use of Otyugh Hole for Iron Will, although since there are several open feat slots there is an eye towards potentially eliminating that.
Also, both spell progressions max out at character level 14 (X2/Riftwalker4/Nar Demonbinder1/Ultimate Magus 7) so I'm unsure what a good cap might consist of. I could potentially see switching Ultimate Magus for either Soulcaster or Cerebmancer, or if nothing else dropping all pretense of offense and combining Riftwalker with Apostle of Peace.
Any suggestions on entry or potential applications are appreciated.