Yellowstone second thoughts.

This year there's not much snow so roads will probably open up earlier dispersing the traffic and the earlier in the year you get there thins the crowd. Admittedly the weather is likely to more unfavorable earlier, but it's a choice of which is a bigger issue for you. The wildlife is bound to be more active earlier as well. In a roundabout way I'm suggesting you go to YNP first. Also there are stats somewhere on visitation by year and month so you can see for yourself.