No Epona. Obtain the bunny hood, or stand on the crate in front of the barn and pick them off that way.
Watch your map, aliens come from behind the house to the barn, so that's a little tricky, and keep out for the dog, it will bark at the closest alien. Don't forget that the crate you're standing on also has arrows inside it. Roll into the crate when you have less than 10 arrows to replenish, and keep firing away.
I recommend not using the inverted Song of Time. They will move faster, but it will be over quicker, with less chance of running out of arrows.
Cain is for Charlie and Delta is for Cain. By Zeus' nipples, that's hawt.