I did it with only playing the left player some time ago. so there is no trouble with the right one
As far as i remember i first destroyed the upper left cpu and capped cp next or same turn, using a kev. guerilla/delta (or if you have ranger). then proceeded to middle and upper right one. You can do that with 2 players as well, the right one has to defend in the beginning and can help after capping i think.
If you see me online, i could try to help you. message me in global chat (somehow no one can message me private ingame).