Weird, I got notified of a reply by email but now it's not here!
I'll have to decline the multiplayer invite, I'm afraid; it's just not my thing.
Congrats on the first castle! That's a big achievement. I didn't realise how hard Native was, and I've become frustrated at how grindy it is to a) get enough troop capacity to be a threat and b) how grindy it is to get those troops to a decent level.
Bear in mind that I've just lost my castle and all its troops; was playing with one save so I'm back to square one, if you discount my honorary title of Dyeworks King of the northern lands!
So yeah, it's been good getting to grips with it again this weekend but I think I'm done with it now for a while (though the temptation is there to see if I can rebuild).
How many men could you command when you took your castle? My 81 wasn't enough against the thousand men who came to look for it back.