The closest thing to "cheese" and having predictable outcomes is to consistently go against lower CR creatures. An 8th level character still gets 200 experience points for a CR1 encounter. Grind that out 45 times and that character is now 9th level. That now 9th level character can now go after a CR2 encounter only 40 times to become 10th level, and after that 40 encounters for a CR 7 levels below character level will net the character a new level.