For starters, what you described "Was about the size of a large Golden Retriever but much meatier..." - um, that's not a small Moutain lion. That's a BIG Mountain lion. Second, for what it's worth (and I realize it's hard), don't ever run from lions....that's what their prey does. The best thing is to raise your hands and make noise. Like I said, easier said than done. Glad it turned out okay though!