Designing Space Ships

Any tale involving space travel needs a space ship. These can be simple affairs like those in Buck Rogers. They can be big, elaborate affairs since space has no atmosphere to create friction.
My tale isn't set in space, but my aliens arrive in a space ship. I get to design a space ship! There are considerations.
First, the ship must fit in the Ozark ravine.
Second, the ship must accommodate the crew of three plus six passengers plus supplies plus necessary ship details like engines.
Third, it must be fairly simple as I don't want to spend lots of time on designing some elaborate affair that would detract from the story line I am planning on. (Yes, I do have some plot ideas.)
Considering the occupants are up to four inches tall, a foot high ship should be sufficient. That gives me a height.
A width of eight inches should work for seating and cockpit controls. If I make it a foot wide, that gives room for hardware.
How long? How much cargo space does it need? How much engine space does it need?
Much of the ship's engines and control hardware can be under the floor of the main cabin. After all, the occupants don't need the entire height.
The ship is a general transport, the last of a convoy ferrying children to a new space colony, followed by supply ships. So, it doesn't need to have lots of supply room. Indeed, part of the cargo area has been adapted to carry passengers.
The length will be 24 or 30 inches.
Maximum space will be available if the shape is elliptical.
Will this design work? It will fit in the ravine. It will hold the occupants and supplies. It is simple. Those were my criteria.
That leaves one last hurdle: Am I happy with this design?
I'll think about it.