Let me try to rephrase or hopefully enhance what /u/NobodyByChoice said:
The entire Marine Corps exists to train or administratively manage Marines in preparation for a MEU, or if we turn the war machine back on, an RCT or MEF sized deployment.
The purpose of a MEU is to be a Force in Readiness already floating around on a ship, surrounded by other combat & support ships checking in on our country's friends and interests.
A MEU is 2-3,000 Marines quite literally looking for a fight.
There are some MOS options that are unlikely to be tasked to a MEU, and are more likely to be assigned to an administrative element that supports other Marines.
But there are damned few MOSes with zero-chance of being tasked to a MEU.
So if you really want the benefits of US military service, but you won't to avoid as much risk of combat exposure as possible, the Marine Corps might not be the best service branch to choose to volunteer for.
Big Army and the Air Force and even the Navy have way more administrative and facility-service elements than the Marine Corps does.
This book: Tom Clancy Marine: A Guided Tour of a Marine Expeditionary Unit is a little out of date (written in 1996). But it is still fundamentally accurate, and informative.
This one is a bit dated, especially since the Corps is reforming itself as coastal defense, but it still stands as valuable to understand the significance of the MEU.
Tom Clancy: Marine: A Guided Tour of a Marine Expeditionary Unit
With The Old Breed; Eugene Sledge
Helmet For My Pillow; Robert Leckie
Are you already a Marine Reservist or are you thinking about joining?
I'm trying to shape my response to the right audience.
Your post history sounds like you are ANG, so forgive me if my response tells you things you already know.
https://en.wikipedia.org/wiki/Organization_of_the_United_States_Marine_Corps
https://en.wikipedia.org/wiki/United_States_Marine_Corps_Light_Armored_Reconnaissance
https://en.wikipedia.org/wiki/4th_Light_Armored_Reconnaissance_Battalion
https://www.amazon.com/Marine-Expeditionary-Clancys-Military-Reference/dp/0425154548
> What job codes do they have at that unit?
Grunts. Armor Mechanics. Radios. Intelligence.
> What vehicles do they have at their disposal?
LAV's; LAV retrievers maybe; 5-tons; Humvees
> Do they ever work with aircraft from other units?
No organic air assets in a LAR Bn to my knowledge.
They are not prepared to assist with Air either.
I've been out a long time. I suppose it's possible they have access to lightweight drones now.
> Are they considered a good unit?
LAR elements are good units, in the general sense.
I was active duty. We generally hate reservists.
LAI / LAR are light weight Tanks. They are generally more mobile than big fat Abrams, and are savagely lethal against Infantry.
https://en.wikipedia.org/wiki/LAV-25
Our LAVs are completely outmatched by any proper tank, since unlike an M2 Bradley, the LAV doesn't have a TOW Missile Launcher.
> Do they ever go overseas for their AT?
AT as in Annual Training? Not likely. USMC has a HUGE training facility at 29 Palms California.
LAVs are expensive toys to move around.
> How do people make it there during a winter shitstorm?
Make it where?
Standard USMC procedure for enduring cold weather involves a woobie and shivering, combined with "sucking it up".
The Marines are NOT known for well-funded logistics. Marines make do with what we have.
> I imagine some people live quite far since there aren't too many units in New York. Will they put you up in a hotel if you're >3 hours away? Please feel free to throw anything else in.
Those are all legit reservist questions, and I'm sorry I have no idea.