Honestly, I'm a little bummed out.

I first joined a Faction, conquered with them, but eventually the Daimyo stopped making wars. No other clans joined, either, so I guess it was a reasonable decision, but also boring.

So I split off and founded my own Kingdom, went to war, conquered, and...couldn't get anyone to switch sides to me, no matter how unloyal they were or how good my relations with them. So I had to consider either of the following two options:

1) Conquer all of Japan with only my own clan, which is doable but also extremely grindy, repetetive and un-fun.
2) Stop playing because ♥♥♥♥ that.

For now, I chose 2).

Not going to lie once I conquer all of Japan I never want to play it again

At some point, no matter the mod, the game always ends up being like this if you want to conquer the whole map, same with warband, its just endless taking castles, defending, til the map is yours.
I always either take a break from the game long before i conquer the map, or start a new playthrough, since the mid game portion of the game is the most fun for me.

hey choo choo how did you start your own kingdom i cant find how to? i have a castle and great status but i cant form my own kingdom to start recruiting lords to me to start taking cities so if you could tell me how you did that would be great.

@gimli: Just like in vanilla. Be independent (not vasall, not merc) or simply leave your kingdom and keep your fiefs. Put a governor in a fief et voilà, you have a new dialogue option with him.

@choo: get some charm. at ~150 you can start to recruit other clans with low chances. focus on clans without fief and with bad relations to their daimyo. And have money, lots of money (cheapest clan was ~200k most expensive >700k). Even with 330 charm it is far from guaranteed to get them (roghtly one out of three)
i am courrently playing a match with 24 clans steamrolling untill war exhaustion kicks in with a social/endurance build. so far the enemy has never had a chance to cap anything of my kingdom.