Comstock is not going to be elected Governor in 2017 (especially since it seems likely she will be running for a Senate seat), and I doubt she will run for President in 2020 after just three years in the Senate. Norm Coleman also has terrible approval ratings in MN, and has almost certainly left politics permanently; if he has not, he is likelier to run for Governor than for the Senate.
But, in your hypothetical scenario, an incumbent President with negative approval and such incredibly negative personal favorability ratings would lose to a competent challenger. Map along these lines, though several Democratic-voting states (NV, CO, MN, WI, PA) are won very narrowly, while no Republican state is closer than ~3% margin (VA is closest):