I am flying into LAS on US this week and my girlfriend is picking me up. I have some heavy luggage and I'd like to make this as convenient for her as possible, as (a) it will be very late for her and (b) she's not that experienced a driver. If it were me, I could find my way around to the curb or the short-term parking and into the terminal, but I'd like to make it easy for her.

I've picked people up there before but haven't really paid attention to what I was doing, and I think the last couple of times it was Terminal 3.

Can you pick someone up at the curb at Terminal 1? Or do they have to use short-term parking? What instructions can I give her to say "Do this and then look for me, I'll be waiting at the curb." Or "Park here and walk here and I'll meet you."

Curbside pickup at baggage claim is not allowed at any terminal in Las Vegas. All picker-uppers are directed to drive into the parking garage and park in the short term area. The first 15 minutes are free, so if all the timing works out just right there is no charge. Or (again, if the timing is right) the driver can pick someone up curbside in the parking garage at the designated passenger pickup location.

Source: https://www.mccarran.com/Park/PassengerPickUp.aspx

Last time I picked someone up at LAS T3 I drove around the airport like 6 times looking for baggage claim. It turns out the traffic signs say "Taxi and Limo Entrance" or something like that. I didn't drive in, so I can't tell you if you get a ticket for it. Heheh.

IMHO the best use of time and energy is for her to arrive early, park in short term parking, and wander around the parking garage until someone with a Smart Cart full of luggage comes out and unloads it into their car and drives away. Then she can take the cart and meet you at baggage claim. Yep, you pay for parking, but you don't have to pay $5 for the cart, so it balances out.

If you can manage your "heavy luggage", I suggest you do the work and make it easy on the girlfriend.
Make your way upstairs in the terminal and head over to ticketing. Exit outside and wait for her at the "Departures", rather than "Arrivals". (where people and taxis are dropping off passengers).

I do this often. If it's late at night, all the better, easy for her to pull curbside. I have never had a problem, and voila, no parking fees or problems finding your ride.

Terminal 1, go to the far end of the ticketing, past Southwest Air, just before the up escalators to get to C and D gates. Exit doors. You tell her to drive to the furthest end of Terminal 1. Best place to pickup.

Typically at LAS, passengers wait for pickup at designated curbside pickup areas. Whether T1 or T3, the columns in these areas have numbers on them. So if you want to have your girlfriend pick you up in this area, head out to curbside pickup and tell her the terminal and number of the column you are at, and then all she has to do is look for the column number (a lot easier than looking for an individual passenger).

If you want to make it as easy as possible on her, have her park in short term parking and then have her tell you where she is. Then you go find her. Then she doesn't have to drive around at all; she just has to park at the right terminal.

That's not correct - there is a designated curbside pickup area at both T1 and T3. Cars picking up pax do not have to go into short term parking. As per the link you posted, what is not allowed is cars waiting for passengers in this area.

Actually, it is correct as written. What I said was that curbside pickup is not allowed at baggage claim. Yes, curbside pickup is allowed in the garage area, which I said at the end of the same paragraph. But that is nowhere near baggage claim at LAS.

That's not the part I said was incorrect. You snipped out the part of your post that is incorrect.

Well okay, if you want to look at that sentence by itself.... but the last sentence starts with "OR...." correctly identifying that the driver could alternatively choose to do a curbside pickup there in the garage. If you read the paragraph as a whole it is correct.

Or, just take the easiest way, and get picked up on the Departures level, as I suggested. Much quicker and easier for the driver.

The past couple of times I needed to pick up anyone at LAS, I had them take the shuttle to the Rental Car Center. No traffic, parking meters for short term parking, and free smart carts.