Physically, the ship was one of the more attractive of FASA's designs, with only the nacelles being "cut'n'pasted" from the movie Enterprise. It was a very clean-looking ship - in keeping with what Rick Sternbach calls the "Starfleet-clean" design philosophy, and reasonably armed, with two phasers and a pair of torpedo launchers. The stated crew of 77 was overly optimistic. I found in doing these deck plans that only about three dozen will fit, less than half that number.
Many fannish artists have done their own treatments of the Ranger class. Most have unfortunately tried to make it look something like a small Miranda class, unsuccessfully (IMNSHO). Most have also tried to scale it to the Constitution refit nacelles, but the ship is actually very small - only 86.8 metres (284'-9") long overall, making the nacelles only 50.5 metres long (165'-7") long. I don't think my rendition is "superior", just more in keeping with the original.
The writeup and adventure give us some facts we can use - the ship has two forward single-mount phasers, two torpedo launcher (one each forward and aft) and two standard shuttlecraft. The ship has a simple saucer-shaped hull with a large shield-type layer on the bow with a large opening, which appears to be the shuttle bay. The drawing above shows the phaser beams firing from either side of the shuttle bay.
According to FASA's "Reference Stardates", the Mk I Ranger entered service in 2270, with Mk II (which is the version shown) entering service in 2275. The Mk I would therefore likely have had nacelles similar to the earlier pre-refit Constitution class.