Holy crap... I spent 75 hours to platinum the game and I was level 168 or something but I did do that farm at Mohg's palace that gave you 100k in like 5-10 mins depending on how fast you kill the spawns.
Yeah,I am trying to go there now but do you really need to do 3 invasions ? also theres is another way but you need Niall first...there was aanother glitched way to get there without killing Niall by jumping off a cliff in Mountaintops,that would activate the Consecrated grounds Statue of Marika lol...guess they patched it.
Also,I was a heavy sneaker in Limgrave,thats one reason my time is high