It's not as if the math would have to be particularly exact. What matters is travel time. And even if speed is fixed, the distance can be freely fudged, since the start- and endpoints of Trek travel are typically fictional - or at least one of them is.
If some writer chooses a worryingly short time of interstellar travel, we simply decide that the two stars were exceptionally close to each other, as long as short times don't become a bad habit. And long times are no cause for worry, since two stars of interest can be arbitrarily far away from each other. Minor variation in travel time between repeatedly mentioned points A and B can be explained away by various means, and major variation just gives us an opportunity to postulate an additional off-camera adventure that slowed down the anomalously long transit!
Timo Saloniemi
"...And that's how we freed the Artemis cult on Blobleep IV. Now let's get back to this problem with the Borg!"

I just ask for consistency and reasonableness in their fictional destinations. Like, no Kronos four days' travel away from Earth. And, frankly, DS9 being so close to Earth is a bit of a bother, to the extent that one has to just assume the Cardassian Union was around in the 23d century, on the other side of the Federation, and no one ever bothered to mention it. Although actually the thought of Cardies in TOS-era makeup, with TOS-era ships, makes me giggle--I should probably be on some kind of medication.
It'd be nice if the rebooted universe would hire Geoff Mendel, and have him make a new, ground-up star chart--a variation with the goofy parts modified--and they should stick to it religiously. But I doubt it will have so many installments that consistency will be a great imperative (it already kind of isn't, with the Delta Vega thing). So, with that foreclosed to any potential prime-u Trek writers (and Treklit writers), just... don't do speed of plot. Do speed of sense.