Fastest campaign path for all upgrades/most gems??

[Speedo]

Looking for the shortest and easiest campaign maps to go through to get the full upgrade tree. I've already gone revolution and carnage and challenge and parts of the other ones. Any suggestions?

[tamtam12345]

Gorgon delight is fastest.
Ambition:fast before red coast,red coast is very difficult to get 3 stars.(get crossbow upgrade first)
Paths of rome and Kingdom come:interesting and fast if you are strong
Age of nyadhos: difficult and good balence ,really needs strategy to win
Maximus:Win attack of north (only build flying tech,two O(fly one) to destroy catapults and one worker to repair .
Fire war:restart if you convert miss in round one.Invasion is very difficult to get 3 stars.Others are easy.

[Disco]

Also, if you haven't yet, the Fiction maps section are pretty good too mate

[COOLguy]

Good suggestions.
Also the "Revolution" campaign is very easy (if you skip two long maps)