Just spent the past five hours at WNW. My five year old and I had a GREAT time, mainly because the park was not busy. Staff reported that because today was a "slow" day that there was not a rental fee for the water tubes.
My little one who met the minimum height requirement (42') for the majority of the water rides preferred to spend her time at the kiddie section and wave pool.
I did bring water bottles and sandwich bags with snacks into the park with no problem. I left my bag unattended with no issues as well; I did not need to rent a locker.
Cost was $73.00 for both my daughter and I but price was worth it because my daughter had a wonderful time. Save yourself a headache and visit the park during the week while school is still in session. I love that we now have a water park in fabulous Sin City.