I remember you drove a tank for 2 hours to get to the strats, it took me 5 minutes to kill ya
semp
That's part of the risks involved with that kind of mission.
I sit outside the range for flashing the strats until high buffs attack them which causes the flashing and all enemy to be climbing after buffs.
I usually use all my rockets and most of my shells to destroy the buildings and then drive just outside of the city flash limit and kill the train that supplies the factories I just shelled/rocketed a few times after that.
Most of the time, the enemy never knows I had been there unless they notice that one of the strats is near below 30% and stays there for a long period of time.