Being able to see the interiors of sister ships to the Enterprise is fairly easy by simply using established Enterprise sets. And it establishes that those sister ships don't differ drastically from the Enterprise. Showing interiors of other types of Starfleet ships might be done with some mild redressing of existing sets. From what we saw of the freighter Huron in TAS' "Pirates Of Orion" perhaps the control room could be a redress of the Enterprise's Auxiliary Control set. I imagine showing the interiors of alien ships could be more challenging. A recreation of the cramped control room of a Romulan Warbird seen in "Balance Of Terror" could be cool. In "The Enterprise Incident" the interiors of the Romulan warship were mostly redressed Enterprise interiors I believe.