This ship gave me a few fits trying to work out its details on my own.
The first was size. It could be considered to be any size at all, but to justify it I could only appeal to the two known sizes of nacelles - those of the Enterprise or those of the Galileo shuttlecraft. Using the Enterprise's nacelles really made it larger than I personally wanted, while using the shuttlecraft engines made it much, much too small. (The only way a human could ride in it would be with one leg in each of the lower wings and the torso in the upper wing. Although it is fun to think of the "hippies" riding six-in-a-row on such a "space motorcycle," I do not believe that was what was intended.) Mandel solves this by using a third size of engine, that established and scaled for the animated Sherman-class starship.
The second problem was its appellation as a "space cruiser." This is obviously different from the Enterprise's status as a "cruiser," the space hippies are not treated as ones who had previously hijacked a Starfleet vessel. I am treating this "cruiser" as being a "cruise ship."
An obvoius question is why a Federation ship would look so Tholian (or, possibly, why a Tholian-flagged vessel would have Federation nacelles). The answer recently came to me from the game Star Fleet Battles, which, for their own purposes, wanted a web strengthening ship (with the restrictions described in the main text). They had also limited their Tholian's cargo moving needs and abilities, so that the freighter hull on which this Web Tender was built came from the Federation. Although this game uses its standard freighter outline on the Web Tender's counter piece and Ship's Status Display, I see no reason against (and some logic for) the ships being built with a family resemblance to the rest of the Tholian fleet. Hence the history given. (The Antares shipyard was chosen at random, influenced by the confusing Antares class(es) in the current Encyclopedia)
One final problem is that although it is designated S.S. Aurora, implying that it is not Starfleet, fans give it an N.C.C. number (NCC-C1200) suggesting that it is. My partial solution is to give both Starfleet and civilians this ship in two configurations; personnel transport and freighter (to be converted into the Web Tender), perhaps the civilian ships are subject to being impressed to Starfleet service.