The alt delete option would be a nice plus, not sure if savings would out weigh the cost involved or not.
LED lights bright enough for head lights cost ~$100 for a pair based on fog lamps which draw 15w x2 and depending on the room, you could ideally gut the back side of the head light assembly and mount the fog lamps inside there, at least that is my plan if my DIY approach is a fail. Here is an idea of what the differences would be, I drive mainly at night (midnight shift) so I need to see well since my trip is 70% along fields and see deer very often and hit one last winter on the express way.
I don't know off hand what kind of draws everything else takes, but your current double battery setup should last your trip if you was 100% converted to LEDs, night or day.