Some first thoughts on my first thoughts here...
*More starting gold (35?), and possibly starting with two lieutenants instead of one, with the option to buy a third lieutenant.
We tried thirty gold and one starting lieutenant. Nice in that it permitted both players to build a decent army and a so-so army and start moving immediately.
*One extra first-level Quest card during setup.
This certainly didn't seem to hurt anything. If nothing else, it still gives you options for questing if one of the objectives just isn't going to happen.
*Tax revenue increases by one coin for each region of the kingdom a player controls.
This might need a little work. One thing it definitely did was let us get more expensive expansion units into play. It also meant buying more market cards. But it might be better to only give the bonus if a full kingdom is united, to further incentive kicking up the veggies in the enemy's garden.
*Victory points are earned for each round a player has unified a kingdom (i.e., controls each region), one per region the kingdom contains.
No way. It was immediately obvious that anything more than a one-time bonus would break the game and make questing pointless. But that four- or five-VP bonus was a nice alternative to questing.