There wasn't a 2012 Democratic primary. Not a meaningfully contested one anyway.
In New York State in 2008, Clinton beat Obama with support coming from both urban and rural areas (with Clinton perhaps doing better in rural areas than Obama):
It's also not necessarily the case that the turnout for past elections will be a sound guide to the turnout for the next election. A lot of people vote as a result of affinity for a particular candidate or because of a motivating issue.
In New York State in 2008, Clinton beat Obama with support coming from both urban and rural areas (with Clinton perhaps doing better in rural areas than Obama):
http://uselectionatlas.org/RESULTS/state.php?year=2008&fips=...
It's also not necessarily the case that the turnout for past elections will be a sound guide to the turnout for the next election. A lot of people vote as a result of affinity for a particular candidate or because of a motivating issue.