Vegas Cup is very fun and competitive for youngers, this tournament turns crappy for older ages. I will take advantage of the Vegas environment while is competitive. Kids will remember their Vegas experiences for many years, reinforcing their soccer expectations and goals.
State Cup will be forgotten next year. At the age of your girls, creating a fun environment playing soccer is more valuable than win state cup. State Cup titles are good for coaches resumes or team rankings, no credit for players at all.
I'll go to Vegas and have fun, over State Cup. Just be responsible and use only the spare time to gamble. What I used to do in my past years at Vegas is to rent a house away from the strip and keep my players there. You can have parents and players enjoying the trip/tournament if you do it right. Enjoy either decision.