I have scored 601 in a real game so yes around 600 is doable but not common. I guess a average score is arond 570-580.. In here I have scored around 590, don't remember exactly..
I just lost 560 to 576. Extremely fantastic game from both Maleb and myself. The only downside is we made small bets to save rolls early then pretty much rolled all high scores for the rest of the game. We didn't need our rolls anymore but didn't have blocks to score higher. Easily could've gotten to 650 or so if we knew we'd be so lucky later on.