Ike to Kerbin

[Lunar Sea]

My ship is in a somewhat inclined (15deg or so) 20km orbit around Ike. I've got 880 dv left. What's the most efficient (and reasonable) method to transfer back to kerbin once the window comes up? I'm thinking ejecting from Ike into a Duna orbit that puts the Pe more or less at the correct ejection angle, then burning from there. 

[Snark]

I'd say just do your burn from Ike as if you were in an equatorial orbit, and add however much normal / antinormal component you need to cancel out your Ike orbital inclination.

15 degrees is pretty close to equatorial, and low-orbital velocity around Ike is pretty low, so it's not going to make that big of a difference to your total dV expenditure.

[Empiro]

If you complete it in a single burn from Ike, it'll be more efficient due to the Oberth effect. You should eject such that it puts you prograde along Ike's orbital path, and Ike should be at the correct ejection angle to get to Kerbin.

You can probably reduce the inclination along with your ejection burn (it may not even be necessary).