Well The Enterprise has various science labs,engineering labs,weapons storage,Cargo bays, several Shuttle Bays ,Life pods,schools,cantinas,shops,Hydrophonic gardens,probably some fitness facilities,training facilities,weapons systems and a massive computer mainframe.It probably has restaurants,several bowling alleys,Swimming pools,Sports facilities, nightclubs,duty free shops,congress facilities,emergency facilities,dilithium and antimatter storage facilities(which have to be magnetically enclosed) and numerous back up systems.And roughly 70-80% of the ship is dedicated to propulsion alone.