Fastest way to level up?

[King-with-a-K]

I pulled out the ol' PS3 and am playing this game again, the most concerning trophy to me is hitting level 37. I have most of all the trophies from my first run of the game, but unfortunately I lost that save so I need to start over. I am going for all the quests with persuasion for 50 persuasion attempts, and plan to travel the maps to get the lorestones. (the only 3 trophies I need to focus on, all the others will fall into place as I go for these)

 

However zones get level locked when you visit them, I found this out after exploring a little over half of the western zones. I am currently level 13, and I am wondering whats the fastest way to grind? What is the most efficient way if I want to "speed run" levelling. I don't want to do sidequests unless needed for persuasion attempts. 

 

What my current plan is, is to clear zones and use my reckoning mode when dealing with the biggest groups or biggest enemies in a zone, and sleep continuously and repeat until the names of the enemies turn green. At level 13 I can get 3K exp from a reckoning mode usage. Once the names go green, I will move and lock in a new zone. rinse and repeat. However I feel like this will end up being slower than my greedy self would like. I was wondering if someone knows of a faster way perhaps? If I get no response since this game is pretty old and has been replaced with a remaster, I will just do my method. 

 

 

 

PS: I have seen threads on the Re-Reckoning edition of the game that mentions a duplication glitch with buying back an item, and you can continuously buy it back. I was under the impression from one of the articles I read that this glitch was actually a prior-existing glitch with the original game (This one), however I cannot duplicate my items at all. I was planning on duping some exp potions. Can anyone confirm that the duplication glitch does not work with the PS3 version?