While the question asks for a "Lagrange Point orbit" and current answers mention that Halo-type orbits (about Lagrange points) are slow, typically about half of the primary orbit (so of order six months for a Sun-Earth L-point and two weeks for an Earth-Moon L-point)
...let's see if we can spice-up and thicken your plot.
It doesn't matter that L-point orbits are unstable, everyone dies way before a station-keeping maneuver would be needed to prevent drifting out of it. Other answers explain that you could put it just about anywhere (L-point orbit or not) and the cast -- I mean crew -- can die in cis-lunar space before it goes far.
So what you need is an interesting orbit for your story line.
The collection of paths that lead towards and away from L-point halo orbits are called stable and unstable manifolds, respectively. The cast -- I mean crew (I did it again!) -- would certainly be traveling near one of those if they were going to a space station in an L-point halo orbit (Sun-Earth or Earth-Moon) and so it is conceivable that if they missed a burn or two they could end up drifting into a nearby halo orbit, or the same orbit but ahead of/behind their target station.
In this case they could even drift in and out of visual range of the station if you liked, and left them figuring out how to get just the right teeny-tiny bit of delta-v that would get them within space-walk range of it.
They could look for ways to give high velocity objects, a bunch of explosive bolts or venting high pressure something in just the right way...
Six months for a single cycle in a Sun-Earth L-point orbit means as long as it's close their craft will be there for years.
But for a two-week Earth-Moon L-point orbit the Sun is pretty aggressive perturber and they may get kicked out after several cycles.
A really interesting twist might be to consider the orbit of TESS which has been worked out to be relatively stable in the Sun-Earth-Moon system.
For plot thickening and historical intrigue, you might consider a frozen lunar orbit instead of a Lagrange point orbit
or even a cool, crazy-looking "minimoon" orbit!
There are zillions of possible unstable, chaotic but long-lasting "mini-moon" type orbits in cis-lunar space that can be entered from, and will exit to heliocentric orbits. Some of them may even come back and revisit cis-lunar after decades or centuries away from Earth.