If possible, I have a sim purchase a beach, and put the vault of Antiquity, the Fairy Rabbit Hole (sorry, I can't spell it's correct name - it is that dome building that allows you to research fairies), the Fortune Teller's Caravan and a subway station on it. Either of the two beach that aren't classified as beach lots in Sunset Valley get this treatment from me. I believe the vault of antiquity and the fairy rabbit hole are two of the locations that things need to be brought to in order to meet the requirements of the single Alchemy Opportunity in the game.
Currently in Midnight Hollow, my family bought one of the empty 64 by 64 lots across the road from each other. On the other one, I placed the premade alchemy consignment store in one quarter. My intention is to put the Vault, Fairy Rabbit hole fortune teller's caravan and subway station there, probably along with a broom track. As founder is a witch. she has nice and easy access to the store to purchase needed supplies, and once all those other buildings are in place, it'll be a virtual one stop shop for all her witch needs.
I do that for no other reason than ease of access