I have been working on the exact same thing, a Tuigan Horse Archer, though im not nearly complete... i would be happy to trade ideas and give some pointers ... though my first suggestion is...
IF going Ranger/Cav... i have come up with 2 variations (but still in test for both)...
21 Ranger/ 4 Cav / 3 Rogue - My thought is if going this heavy Ranger, may as well go for Bane of Enemies and take at least 3 Favored Enemies (mainly the hard to get ones, for Studied enemies...) My first thought was Elves, Half-Orcs, and Halflings, Then fill out Studied Enemies... and Reason for Rogue 3 is just for the better skill selection (Tumble, UMD, etc) and a couple sneak DMG die... though at a loss of the Spirited CHarge bonuses, and only a T2 mount
or..
23 Ranger/ 7 Cavalier - Same as the above, but we are sacrificing the Rogue Levels, to get T3 mounts... and get Rangers Bane of Enemies, but also Call of the Wild... This will make the companion more useful, more overall damage to any race on your favored/study list... at the cost of Tumble and UMD from no Rogue levels... Now, just so you know, because i did not at first... while mounted i read Tumble does not improve AC while Mounted, only riding skill does... but it still helps off horse..
Also i should ask, are you more Str or Dex based... i assume Dex, but it could help to mention your stat allocation.. Also is race of your character specific, because i have also come up with some other variations such as Fighter/Rogue/Cav as some alternatives
Though, if you want to exchange builds, im still tweaking mine for both, in the PGCC... so if you want to exchange thoughts and ideas i will try to be more attentive to the forums...