So this may or may not be common knowledge but the other day I was trying to figure out a way to get to thealien ship. I found a way in the NW corner where all the wrecked cars and radioactive pool is. Funny enough seemed to only work if I went through backwards while jumping. Extremely pleased with myself I worked my way over to the ship and to my surprise it was the same one from F3,cracked canopy and all. =-O