No way dude! Gondor is the faction of honour. They dont plunder around. Face the enemy! I was able to take back the two southern citys back as gondor and holding Mordor behind the mountains (VH/VH). But that was only short time success. Weary forces had nothing to put against the new and stronger stacks of Harad. And my economy being in minus was not able to recruit new troops and stop the red wave from the south.
I thought about taking all the starting units from the south and the middle in one big stack and take the small rebbel-settlement above the river. the troops in the west should be able to take the rebbel-settlement in the far west. then bringing this troops to support the fight in the south...
I wanted to try that but I decided to start a new campaign with Rohan wich is very successfull till now (78).
Biggest problem in the south are the weak troops of gondor. so u have to build up population asap. then u should be able to build spear-troops!
Good luck, but stay honourable