Vacation Days is written by D.B. Sommer, and can be found here (http://www.florestica.com/dbsommer/vacation-days/index.htm). And here (http://www.hostultra.com/~AngCobraFics/dbsommer.html). And here (http://tmffa.mikomi.org/old/r-vacation_days.html). And ... how many websites do you have, Mr. Sommer?
ANYway. Vacation Days is a story about Mihoshi. And Tenchi. And a host of very bad people doing very bad things. You'd think the Galaxy Police would try and shut them down, and....
But I'm getting ahead of myself. This is a story that (to me) demonstrates that Mr. Sommer doesn't really write for the characters as much as the setting, and I think that's one of his strengths. He adds some real shading to the setting, going places the OAVs hinted at without spelling out, and it feels to me he drew at least a little influence from one of the movies ... I can never remember which one is which. The end result is a well-written world with memorable characters and (mostly), events.
Mihoshi is well realized as a character that comes across as 'deep enough' without actually taking her from her OAV presentation. A backstory is added that gives her some added depth,
Tenchi's character also comes across as well developed and indirectly produces what is easily one of my favorite lines in fanfiction. I'd quote it here, but it's not, er, entirely appropriate, and it doesn't make sense outside of context. What really impressed me about the story was the cast of original characters who were developed to work as foils/enemies for Tenchi and Mihoshi. It was well written, with no real grammatical flaws, and for an older story (I think; I've only just read it yesterday), it has aged very well.
I highly reccomend it, and considering I almost exclusively read Ranma (and Caravan Kidd) fanfiction.... I give it four and a half of five tin sugar cubes, but I'd have them all bronzed.