When it comes to small planes, weight matters. Don't be surprised when your contact emails you for all passenger weights, and when the pilot organizes seating by weights. (You don't want the three biggest people on the right side, for instance.) Similarly, don't expect to bring two weeks of stuff for a weekend, and definitely mention if you're planning on bringing golf clubs or skis. If they don't fit, check out ShipSticks or LuggageForward, which sends your equipment beforehand for a relatively small fee.
Though the early Lockheed Jetstar had four, most production business jets have two jet engines, mostly rear-mounted podded engine. If mounted below their low wing, it wouldn't allow sufficient engine clearance without a too long landing gear. The HondaJet is the exception with its over the wing engine pods. Dassault Falcon still builds three-engine models derived from the Falcon 50, and the very light jet market has seen several single-engine design concepts and the introduction of the Cirrus Vision SF50 in 2016.