
pad300 |
I am feeling inspired by Victor Milan's Dinosaur Lords series. Thus, I am thinking of building a dinosaur lord...
This will be primarily a martial character, with the intention of mounted combat on a dinosaur...
My first thought was 3 levels of Hunter + Ranger X (including boon companion), but then I started wandering down assorted rabbit holes... Like Sacred Huntmaster Inquisitor in place of Hunter, and Cavalier or Samurai in place of Ranger...
I'm getting lost in my option, so suggestions are appreciated.

avr |

There are a lot of options. To narrow them down you need to apply a few constraints, more than 'mounted combat on a dino'.
Do you want to be a member of the noble caste especially?
Do you want a big dino, larger than a horse, and if so is it OK if that's a temporary effect?
Is obvious magic a problem?
Do you want social skills & charisma i.e. to be a leader?

pad300 |
Ok, big dino (ie Huge or more size), not unless it's temporary. I have seen someone try to use Mammoth Rider in game, and the PC repeatedly ended up SOL when forced into a human scale situation. The AC should be Large for riding, but that's about it.
Obvious magic isn't a problem for me. Nobility is not a requirement. Nor is charismatic/social skills/leadership.
The current tradeoffs as I see them
Hunter vs Sacred HM
Hunter gets an extra teamwork feat (precise companion)
Sacred HM gets better saves (+Will - Reflex), a Domain/Inquisition, Cunning Init, and detect alignment (note that the 4th level of Sacred HM catches up animal focus)
I'd say 4 levels of Sacred HM is a more potent deal than 4 levels of Hunter
The martial tradeoff is trickier - I am thinking of melee style, not missile combat. But there are a lot of options (and 3 of them need to consider archetypes...)
Ranger - needs to get Boon Companion
Cavalier
Samurai
Assorted Animal Companion Archetypes : Wild Child Brawler, Mad Dog Barbarian...
In theory Paladin would also be a contender for the martial, but I'm not really looking for the code of conduct.

avr |

Sacred huntsmaster is better than hunter in most ways. The question is why you'd abandon either for the full BAB classes. A dip for weapon proficiency as an inquisitor sure, but spells keep getting better (share spells + improved spell sharing + channel vigor, stoneskin or righteous might, to say nothing of utility) and you get class features like bane and teamwork feats too. After investing 4 levels it seems like staying the course would be better.

Scott Wilhelm |
How important is it that you ride a dinosaur? How would you feel about being a dinosaur, like a Druidzilla build? Maybe you could take the Leadership Feat, and you'll be an Animal with a Person Companion! That would solve the problem of having to leave your mount behind when you go into the dungeon.
The Arsinotherium has a really impressive Gore Attack, and it is Size Large like you say, but it's not a Dinosaur. It's a megafauna like a wooly rhino maybe.
The kentrosaurus tail attack is not bad for its size, but not compared with the Arsinotherium's Gore.