Even a forest-dweller is unlikely to experience deer musk in its natural context.
Medicinal refers to a variety of different effects. Benzoin is used in both medicine and perfumery; it smells like a "sharper" version of vanilla. Sometimes the description is attached to camphoraceous notes (clove, eucalyptus, menthol). Hmm, probably more. I don't think "city people" are at any disadvantage here.
You can get a small quantity of synthetic oakmoss quite cheaply from suppliers such as The Perfumer's Apprentice (http://store.perfumersapprentice.com/bl-0030.html). I guess small quantitites of the real thing are still used in perfumes (and certainly it is found in older formulations), but the synthetic should be a good reference point.
In general, you'll acquire a good sense of the major perfume notes by noticing what different fragrances have in common. Smell several scents with prominent musky bases* (best: spray them on paper strips and smell the strips several hours later) and you'll get to know musk. (It's a bit more complicated, however: most musks are synthetic these days, and they have a variety of effects, from light and powdery to strong and stinky!)
*try a sample of muscs koublai kahn, kiehl's original musk, jovan musk