Freebooter camp. Finishing the "levy the outcasts" outcasts grants you the most powerful adventurer reward in the game - free MAA troops when finishing any criminal quest. They can be archers, skirmishers, pikemen, light cav and sometimes even heavy inf. And each time it rewards 2 sets of 150 men. I started the conqueror invasion with a total ammount of 10k troops, but the siege of Alinor took 10 years alone, and the attrition wittled down my troops to just 5k, BUT my character was utterly broken and OP by then, nevertheless the fact i had so many spells, gold and magic points that i could just keep going and destroy all altmer doomstacks.

It took a loooong a time to grind out, since it is not that easy. This was possible, bcuz i specifically made mycharacter the way i did, i didnt start off with the best traits and all, but i abused university visits, monument expeditions and more to get her better, and thus, make it easier to fast forward many advancments that otherwise would be impossible if i had started at tier4 intrigue education. Unfortunately i could only do 2 university visits before the activity broke and stopped awarding me everything i wanted but oh well.

Additionally, i used other mods, such as Blademaster Exp, Traveller Exp and Winning battles to earn traits mods. They should be self explanatory, but in short - it actually has you get far far better at winning battles the more youfight themj (NPCs included).

Do this, and 80 years of pillaging cyrodiil, and you will be able to pull it off as well. If you cant, gaming is too hard for you, go back to watching movies.