I'll chime in a bit here Dewey, although I've only ever chased merriams in the black hills, and some others here certainly have more experience with them.
dewey wrote:What is the best thing to roost them with? I have a crow call that I plan to use.
I always have just used my regular turkey calls. Some loud cutting and yelping or gobbling will get them going on the roost, both morning and evening, better than some of the more traditional locator calls in my experience. A friend of mine uses a coyote howler and it also works well.
Decoy's? This question may sound silly but if I have a decoy but it is Eastern tail fan colors does this matter?
When I have used a decoy on merriams the standard eastern colored ones have worked just fine. If all you hunted were merriams, it probably wouldn't hurt to paint the tips white, but I don't think it would make much of a difference. Merriams with those white tips are much more visible from a distance than your standard eastern though. They almost seem to glow in the morning sun. A mature merriams strutting through the open pines on a calm sunny morning is a sight that is tough to beat. I hope you get to see it.
What do I look for in terms of terrain? Open areas in the ponderosa pines? Areas that face southeast for morning sun?
Honestly, just look/listen for birds. Merriams will cover a lot of ground in one day, and the odds of one roosting near where he roosted the night before are about 50/50 in my experience.
In terms of roosting is it best to get to a high point and let her rip and see which way the gobbles come from?
That's what I typically do. don't be afraid to try 3 or 4 different high places during roosting time. again, the name of the game is covering ground.
My plan is to try and roost them the night before my hunt starts so I can get a good place to start in the morning.
That's a good place to start. If you don't hear any gobbles at night, don't get discouraged. They always gobbler better in the morning. Again, covering ground is the name of the game until you can find some birds. It's not uncommon for us to walk 10-20 miles a day. Also, because they move so much just because a certain ridge was silent yesterday doesn't mean it won't be crawling with birds today. One more thing, DON'T try and chase one. If you can't get in front of a moving gobbler it's best to just let him go. They will drag you along behind them like a kite for miles gobbling at every call you throw their way for an hour or more before just disappearing into the woods. I've learned this the hard way many times.
Good luck and enjoy your time out west!