I've been into nature photography for years now, I'm currently using a D7200 and Tamron 150-600. I'm traveling across the country this summer and thinking about upgrading my kit. I'll be taking pictures of grizzly bears, eagles, moose, and some scenery but I'll be far away from most of my targets. Any suggestions for ways to upgrade my kit? My budget is probably around 3k. I'm not necessarily attached to any particular brand or style. What do you all think is the best use of my money?