I've never been to the Platte River, but I cannot imagine it could be better than Cheyenne Bottoms / Quivira. Here's a list-serv I belong to where you can find a lot of recent postings from those areas. This thing is a little hard to navigate, but it might help you make a decision. Also - if you time it right, you might be able to spot the Whooping Cranes!
Good luck and have fun.