Welp...first off, you can drop shot in any water depth; it's just a type of presentation. Although most commonly used "offshore" and in deeper water, it can be used shallow too.
Second, there are always offshore bass; as there are always shallow bass.
And third, I commonly catch crappie when targeting bass offshore. But remember, where there are crappie, there will be bass close by. Sometimes I'll catch 7-8 crappie to 1 bass; you just have to weed through them to get to the targeted species.
When drop shotting, bait selection and color can make the difference between catching and fishing. Color especially can be the game changer. So, bring a few different baits and a few different colors and try them all until you get some bites.