It's not as hard as it might sound. Renown comes hard in the beginning of the game but at you get a number of quests right before the end of the game that give you tons of Renown. Treasure Island of Doom gives you 7500. Rescuing Charlie gives you 5000. T.O.B.Y. gives you 7500. Evil in Wraithmarsh gives you 4000. Love Hurts gives you 8500. And then when you beat the game you get another 10000. Those quests alone add up to 42500. And you should have more then enough before renown built up before this to make up the rest.