Post mortem:
FARM (4): Horse, Rose, Park, Private
CRATER (3): Moon, Boom, Park
DOSSIER (1): File
So I wanted to try to connect Horse, Rose, and Park. I considered FIELD, but Track was one of their words. Also GRASS, but wasn't sure it would really work. Then hit on FARM, which also allowed for Private, but didn't realize it was actually further from Park that natural. (i.e. in my mind, I connected FARM to FIELD, and didn't think further). I didn't even consider that you would somehow think Guitar there...
When I had CRATER in mind for Moon and Boom from early on, when it was clear to me that you weren't necessarily getting Park from FARM, I realized there must be some park somewhere named after a crater, so I threw a 3 on there instead of a 2. And luckily, there is!
Lastly, I couldn't think of a good clue for File and Park, so had to hope that you'd get Park from the other two. I did consider X (as in X Files and X marks the spot, which maybe for park), BUT was afraid you might think Atlantis, since it no longer exists. Also something like CARFAX, but the problem with anything car related was garage. (It really helped that they got Van for us).
Generally, I had to avoid anything transportation related due to Ship being Assassin.