I am trying to write-gineer a realistic, far-future (hundreds of years), spaceplane capable of landing on and taking off of, most surfaces (planets, space stations, asteroids, etc.). To that end, I ask for the community's help in making it as believable as possible. It must be a single-stage-to-orbit craft carrying a small crew ~6 and several tonnes of cargo for trips that could last up to two months.
Why does this ship exist? To exchange cargo with distant colonies that do not have the infrastructure for more efficient systems.
Assume the following engineering marvels have been packed into one, C-5 sized, spaceplane: Power and thrust is provided by an anti-matter reactor. A Harrier-esque VTOL gets the plane off and on the ground from anywhere (without killing everyone below it). A SABRE (Synergetic Air Breathing Rocket Engine) inspired engine gets it into space. Can carry a cargo of about 80,000 kgs. Has enough food and water for 6 people to last 2 months (~800 kg of food plus ~1,400 liters of water). Has quarters and support facilities for up to 6 people. Re-entry is protected by ceramic composite skin. Has laser point-defense systems and mass driver (coilgun) armaments. An Event Horizon-ish jump drive is used for interplanetary and interstellar travel (this is the only piece of ‘space magic’ I would like to use).
Artificial gravity is not necessary as trips between colonies would take, at most, a few months (and usually only a day or two between close systems), but if there is a way to theoretically produce uniform artificial gravity by rotating a spaceplane, that would be a great bonus.
What am I missing and is it realistically possible so far?