I've worked on a set of rules for DBA (but could work for FOG or any ancients rules - provided that the base numbers are manageable). We did run a campaign using Warmaster Ancients which was fun but the battles took hours to complete which affected the campaign running time.
These rules are designed to last for 80 turns (or Seasons) but you can amend length as you like. Note that I have not stated how much Gold and Food each Territory produces - you can make up your own mind as to what is manageable but bear in mind that forcing Players to make choices due to limited resources produces a better campaign where they are unlimited in what they can do.
You'll find a page dedicated to the rules here : http://philbancients.blogspot.com/p/dba-campaign-rules.html.
Hope you enjoy them!