Actually, it wasn't a ton of xp, but enough to make it feel worthwhile for an evening without much combat or roleplaying.
So there was xp for:
- Establish a kingdom
- Build a capitol city
- Grow kingdom to size 5
- fill a city block with 4 buildings
- completing a quest (no spoilers)
- killing some things (no spoilers)
Right now building points are at a premium but it is currently hard to fail an economy check so they should be getting build points every turn, enough to continue growing their kingdom.