TL;DR: This is a two part post. The first part is about Paladin blending with Cavalier. The second part is about adding cleric levels to cav levels. All use Order of the Star. If you only want to help with one or the other, thank you! If you help with both, extra thank you!
Part 1
I can't overstate how much I love the Cavalier. It's such a cool class. It's fighting on horseback, which is everything I want out of fantasy.
It is also very similar to a paladin. I'm not averse to playing a paladin, but I prefer the broader scope of the Cavalier's challenge to the Smite of the Paladin...
Anywho, in looking at the Order of the Star, it strikes me that the two are not as exclusive as they would seem. I could blend the Paladin and the Cavalier over the course of 20 levels and produce some interesting results. 15 Cav/Order of the Star and 5 Shining Knight Paladin yields: Lay on hands 6d6, add CHA to saves of Mount, 2 Smite/day, 4 Challenge/day, full mount with summon 1/day. Minor spellcasting of first level paladin spells. +15 to damage on challenges to nonevil foes, and +20 to evil foes with the addition to the CHA mod on attack rolls, moral bonuses to saves while facing down the challenge target, and anyone that strikes me or an ally with the same faith provokes an AOO. Also, a few times per day I can get my CHA mod AGAIN on all my attack rolls.
That's a lovely end result... however.
In what order should the levels be taken? At BAB 10, you can take the Coordinated Charge teamwork feat, assuming you also have another teamwork feat. This probably means going the Strategist archetype to take an additional TWK feat that isn't useless. So there at least needs to be 1 PAL level before CAV level 9.
If you feel like helping me cook this up, thanks very kindly. There's no guarantee I'll be able to use it soon, because there's no guarantee the next session will have Paladin playability.
Part 2
Furthermore... you aren't restricted to LG alignment. You can take first level of a cleric of any deity and gain minor channeling through your career. This is what I'll probably end up doing if I can't take Paladin. To that end...
What god provides the best set of first level domains that never progress? I would prefer if it was channel positive so I don't have to go out of my way with feats to select around my mount. I would prefer not to hurt my BAB too much and I don't think there's much use for low level spells at high levels. It doesn't blend as well as Paladin, but in this case I could be a Chaotic Good "Paladin" of sorts. What are your recommendations in this case?
Thanks kindly!
Edit: The books I am allowed are hardcovers only: Core, APG, UM, UC, UE, ARG. I see no reason why discussion cannot carry further from these books so long as both with and without are discussed. Thank you!