My current army GP age would ream this base, but here goes: 80 Legion, 24 gunmen, 1 elephant, 1 general, 9 donated legion. First aid, plus Strength of the Gladiator if I've got it.
Drop the 9 donated troops on the top right cat to wipe it. Drop the elephant on the castle, deploy the 40 legion in a long spread along the castle side. deploy the 24 gunmen along the same spot, deploy the remaining 40 legion along the same spread. Give it another 10 seconds and deploy the general. This would cover the castle, coliseum, stable, barracks, then finally the ballista. While this was happening I'd deploy a First aid, or two depending on splash from the cat.
After that put on the first rally point onto the second cat. Once it's gone, it's just mop up.