Pine Knob has a pro shop that probably has goggles, although I don't know what stock/availability they might have.
But there is a Boyne store right on the way, you'll drive right past it if you take....
...As for which hill, Mt. Holly is my favorite in terms of terrain variety. The only reason I really ever go to Pine Knob is because they have a decent terrain park. If you ride park, go to Pine Knob. If you don't, then I'd say the extra 15-20 minute drive to Mt. Holly is worth it.
I like Holly better for terrain & trails, but it's crowded as fuck on the weekends and lifts are sloooow! Mid week? Light crowd? It's Awesome! On weekends I prefer PK myself! (...but I don't do park, so take that into account!)
It's been a while since I was in that part of town, but IIR, from Redford you can get right on I-75 to go straight up to PK or Holly. Although, if the weather & roads r bad? Take telegraph all the way up. For whatever reason, I-75 usually turns into a REAL shit show in weather. Almost always has multiple accidents F'ing things. Telegraph takes longer, but usually moves pretty well!
If you're looking for "good" quality goggles, yeah! Boyne Mt Sports or REI, even larger Dick's stores have good variety to choose from. If you only need a cheap pair to get you thru? Go to Dick's & spend $20-$30! Boyne store @ woodward & squarelake is HIGH priced cuz of the neighborhood!
If I was going to be around this week, I'd sell you my old pair of Scott cheapies for $15! Used only for my first 1/4 season! (might still b overpriced!)