You can, especially with very low part count. A high-part-count craft will be flying at about 27,000m accelerating just barely, while the fuel burns at full throttle. A bigger portion of the fuel will be needed for the jets, this can compromise the interplanetary capability. If you're going for less intakes try to avoid putting dead weight like girders, i-beams, tail cones, NCS adapters... Engines are dead weight too: If you're going to Laythe you don't need high TWR in space, so minimize the rocket engines.