Peter the Lefty
All right, there was one that was done a while ago on this, but it's died out, do I figure I may as well start anew.
Conservatives: Being the result of a merger between the PC's and the Reform Party, it would now represent a moderate conservative position, gaining most of its support in the Mid-West, the right-leaning parts of New England (like NH), and in places like upstate New York, subrural/rural Pennsylvania, as well as Florida, rich parts of California, Nevada, and elsewhere along those lines. Would've once had the South as its major base (since Reform would've sprung from there), but the South would now be turning mainly to the CHP and the Libertarians.
Liberals: Would be strong in middle and upper class urban areas and the suburbs of NYC, especially in the financial district of Manhattan, and in the greater NYC metropolitan area. Would be big in Connecticut and New Hampshire (especially with Martin), though it would've gone to Harper in '06 and he would've kept it in '08 and 2011. The Liberals would also do well in lots of the richer but socially liberal suburbs of Pittsburgh, Philadelphia, Springfield, Illinois, and the rich parts of Los Angeles, San Diego, Austin, Dallas, San Antonio, and Houston. Would also be well-liked in New Jersey.
NDP: Considered a far left hippie radical tree-hugging socialist party in the American context, it would be strongest in Vermont, Massachusetts, Rhode Island, almost all of NYC (at least as of 2011, if not before that), downtown Philadelphia, Pittsburgh, Scranton, Delaware, D.C., Chicago, working-class Los Angeles and San Diego, most of Oregon, Washington, and in the super-liberal and working-class parts of Austin, Dallas, Houston, and San Antonio. Would also have pockets of support among the working-class/poor black populations in much of the south, even though they'd likely be a bit put off by the party's gay-friendliness. San Fransisco would, of course, be their most reliable stronghold, possibly even voting for them in '93.
Greens: Far more market-friendly than their RL American counterparts, they'd probably be strongest on the West Coast among the middle-class hippie types who are impervious to the fact that May is just an articulate bullsh*tter.
Bloc South: Would be picking up votes throughout the South for separation thanks to Harper's alienation of his Southern "red meat" Reform base.