GPS, not at all trying to be a smart aleck.
I am not sure which reservoirs around the Valentine WLR you are thinking about. Their a boat load of small lakes in that area. The thing to kinda remember is they are not real deep and have a gradual slopping edge to the small lakes. Obviously all sand bottom.
Yes the fishing in some of those lakes is great and odds of seeing anyone while you are fishing those small lakes is slim.
You are correct about the pheasant and the wetter areas. Didn't mean to imply anything, you seem kinda like me in the respect you would like to not accidentally shoot the wrong bird. Some people are surprised to find pheasant in those hills. They are there, just not really talked about
Halsey is rugged country. Not in the respect it is broken country with rocky land but rather it has serious hills and the footing is sometimes questionable. I got my truck stuck in Halsey one grouse season. Trying to exit those hills in the dark was a white knuckle experience I do not wish to do again.
The "forest" up around Merritt is also very similar terrain, it just has less of those cactus.
Halsey (the city) has limited motels and places to eat. That area of Nebraska is some of the most remote you can find in the state. (the Dismal River up their is really pretty country) Not sure if you wish to camp or motel. Halsey NF has some nice primitive camp sites, and until deer season they should be pretty empty about that time of year.
Water, the water table is the hills is very high year round, more so in the refuge than Halsey or Meritt. So yes you will find wet areas for the pups. Also their is a great deal of stock tanks and wind mills all over.
Still I would consider grabbing plenty of water as when it is warm and you are on the top of a hill, that stock tank looks a long waise off..
The ranchers up their are some of the friendliest people I have ever met. They...umm how to politely say...are not the most politically correct. If you are inclined to ask permission to
grouse or dove hunt only you will probably be allowed to do that. But they are pretty big on the subtle forms of respect. If inclined to ask permission, I suggest being extra polite.
They can tell you exactly where to find the grouse on their ranches.
I really enjoy chasing grouse in those hills but I will say it is the most demanding hunting I have ever done...bring your light weight scatter gun is my advice.