FDR would have some problems with him. Though modern medicine would do much in convincing voters that FDR won't die on them, he would have some baggage. His decision to put Japanese citizens in concentration camps would be his "email scandal", and I suspect this would cause him to loose votes with Asian voters and perhaps a few percentages in other demographics.
His moderate appeal would be very helpful in countering Trump's appeal to white working class/no college degrees; however, his moderate social views would hurt him with social liberals. Additionally, Trump could make the argument that FDR is racist against minorities (because of course he would) and that FDR is not knowledgeable enough on the 21st century.
I'd suspect it to be something like this:
297: FDR (D-NY)/Sherrod Brown (D-OH) 40.7%
232: Donald Trump (R-NY)/Mary Fallin (R-OK) 35.2%
5: Gary Jonson (L-NM)/Bill Weld (L-MA) 20.2%
0: Jill Stein (G-MA)/Ajamu Baraka (G-DC) 3.9%
Gary and Jill play spoiler in New England and the West, but Gary has the same problem as Ross Perot had (except he actually wins something).
