If first class is important to you, I would buy the Y fare. EWR- LAS is notoriously difficult to get upgraded on because of the high demand for paid FC seats. I have been upgraded maybe 1 or 2 out of 10 times on these flight in the past year as a gold on all sorts of fare classes...not too good....

If not, then take the 1000. put it on your favorite number on the roulette table. If it hits, then you can buy an f/c ticket on the way home and have 31 more grand for spending money