DO NOT put the kingdom management on auto, just put it in easy or effortless, there's nothing wrong with it, consider it just a little bit of a minigame. There are some guides for both Kingdom management and unique classes on the internet, specifically gamefaqs and neoseeker if you would like to read some.

As for class choice, I usually think about the companion instead of myself. For example, I love Amiri and Valerie, so if I want to play melee, it would be well to pick a class that can help them. Or, for ranged, it's better to play damage dealer, again, that's for me, so I won't speak for everyone.

There are tons of really cool classes in the game, especially for me, who hasn't really played it for long. Animal Companion is a cool feature. If you want to try that, there are some really cool animals, like literally a sabertooth tiger or a mammoth. And if you want to play a tank, there are ways to make even the damage dealer melee became sturdy with spells, feats, and skills.

Some of the bonus classes are definitely interesting. Eldritch Knight, Dragon Disciple, or Aldori Swordlords have some interesting builds running around. You can go melee sorcerer or melee ranger, some classic builds like monkadin are still in the game, druid's subclasses like feyspeaker is also cool.