Plan is to go Cavalier, Order of the Ennead Star with the Circuit Judge archetype (we're playing a kingmaker esque campaign set in the Linnorm Kings lands, and we get a fort super early on according to the GM, so I'm setting that as my judge community. Also: We fight LOTS of chaotic people, outsiders, and fey.)
The idea is: Order of the Nail decides to expand the boundaries of civilation in the hopes that if they can set up a citadel in the North, Cheliax may be interested in sending further expeditions that way, cementing a foothold in the region. So they send a determined armiger to see what the situation is, while also bringing forth the benefits of civilization and order to the barbarian ulfen mongrels.
I am not very experienced with the cavalier build style, but I KNOW I want a Halberd and Lance. Full plate as well. I've CONSIDERED going Beast Rider also, but not sure if its worth the feat investment in taking Heavy Armor Prof later.
What should I look into as a heavy front line fighter? Goal is to charge in with lance and then swap to halberd.
If you have the Sargava Companion, there is a great feat Rhino Charge which let's one Ready a (Half) Charge,
which is great because you can first maneuver on your turn in order to get a clear Charge lane,
and you can ready a Charge vs. a more flexible situation, not just one specific person.
(i.e. the first person to cast, when you don't know who is casters)
The Pre-Req is Power Attack and Imp Bull-Rush and BAB+5.
I like that. That does sound pretty useful.