Use of objects and prepositions after "do" as substitute verb

Can we place objects and prepositions after do used as a substitute verb? What are the rules?

For example, "we eat vegetables, as we do fruits" sounds ok, if contrived (bad example). "We go to Paris, as we do to Rome" sounds not ok, perhaps because "doing (something) to someone" has a meaning of its own. "I give an apple to John, as I do to Jane" sounds ok. "I give an apple to John, as I do an orange to Jane" sounds uncertain to my ear.