I've had really good luck with EWR-LAS over the last 2 1/2 years (I've flown it maybe 8-9 times?) Here's how I do it...

- If a mileage upgrade is available on the outbound, I take it. F is always a nice way to start off a trip to LAS! Did this 2 or 3 times.

- I always take the 7:35a departure out of EWR on Thurs or Fri. I've been upgraded every time (as Plat in 08 and a Gold now) that I haven't used miles.

- I leave Vegas on Monday (either 2p or 4p), and only missed one upgrade. These upgrades never clear in advance, it's always been a battlefield for me.

I think I've been really lucky and don't think my results are representative of most people but hopefully you find something here helpful.