To add to what Al was saying, if you are looking at how the USA would vote you have to bear in mind that voting
behaviour would be different too. There wouldn't be a wierd obsession with what people do in the bedroom and people would vote on the economy and jobs. Most importantly however, people would vote pretty much the same way they have voted for the past fifty years.
Here's coal seams in the USA (not sure which areas were thoroughly mined however)
http://coalgeology.com/wp-content/uploads/2010/08/US-Coal-Producing-A handy tool to use is this;
http://elections.nytimes.com/2008/results/president/explorer.htmlIt allows you to see areas of poverty, low income, manufacturing etc to see where Labour would likely be strongest.
There are two particular nuances that complicate things. Firstly race. The UK is lucky to have a handful of constituencies with a minority population of over 30% yet the USA has whole states. If black voting habits were the same then Labour would dominate disproportionately in some states. Secondly there is mobility; people in the US tend to move from state to state. This dilutes some older voting habits.
I had a stab at Pennsylvania in an 'all things being equal' scenario
I looked at past voting habits from the 50's and 60's, areas of coal mining, areas of manufacturing, areas of poverty and educational attainment and also %Catholic and came up with this guesstimate for Pennsylvania (the Lib Dems taking the richest county with the highest % of people with a degree)