Kingmaker has a few dungeons that might be of limited space, but it is otherwise much more open than the other Adventure Paths. It's one of the few campaigns where a Medium Cavalier would also be viable for that same reason. I'd be more worried about how a Lion Shaman would fit into the landscape itself story-wise, though I think some felines do live in the River Kingdom areas.
Kingmaker is 90% crazy open territory. It was one of my favorite adventure paths because I played a Paladin and my GM allowed me to ride a Wooly Rhinoceros when I reached level 6. I bought a lance and charged in with powerful charge and my lance for virtually every attack I made against the enemy. It was crazy awesome do double damage on a charge with my lance and with the Rhino's powerful charge damage as well. It was great.
Lots of open space in kingmaker. The only question is why a Lion Shaman Druid would want to become the leader of a kingdom. The kingmaker in the title is literal, you and the party will build and lead a fledgling kingdom. Is this Lion Shaman going to be ok with Living in an urban environment?