If you were hunting primarily in oaks, you were in a low percentage area at best. If the area was only 60 acres and not adjacent to a known producer of grouse, you are unlikely to ever find a ruffed grouse in that area. Ruffed grouse are most at home in aspen from about 5 years after cutting to about 25 years or so. That type of habitat will meet pretty much all the birds needs if at least a section in size and better yet would be thousands of acres.
Your best bet would be to go to the areas you have seen ruffs and start hunting. You will find the birds where they wish to be, not where you wish them to be. Ruffs are creatures of relatively heavy cover so you will have to learn to see the bird, mount the gun, and shoot in a fairly compressed time frame.
I used to look at the crops of birds but no longer. Listing what ruffs won't eat is a far shorter list than that of what they eat and like people at a restaurant, it is not uncommon for the birds to have different foods in their crops. What stands out is when I shot two grouse from the same dogwood patch. The berries were ripe but the one bird had a crop full of clover, the other mushrooms. And not a single dogwood berry to be found though the robins were thick in there.
As for sharpies, I look for regions where less than 50% of the area is planted into crops with the rest grasslands. Start getting more than that percentage and sharptail numbers drop quickly. Grass should be no more than knee high as a somewhat joking rule of thumb is sharptails like to sit up and look over the grass when they want to. It is a reason they are often found in cut wheat, barley, or rye fields. If you would expect to find pheasants in a spot, it is probably not going to be very productive for sharptails.
Some brush is good too, it provides shade and cover to load in. I like seeing loose clumps rather than thick patches as it is easier to hunt. Trees aren't so hot as Hawks often in them waiting to pick off prey. On windy days I've found sharptails on the leeward side of tree lines but a good 50 yards out or more.
Prairie grouse are why I added English setters and a Pointer to my dog string. There can be a lot of country between birds and a bigger running dog increases your odds of finding them. A couple dogs puts the odds a little more on your side. 16 dogs out at once is a riot. Though not always a funny one. I've had my dogs a quarter mile out and that can be pretty nice when you have several sections of land to cover. As long as the dogs are staunch on point and both of you are able to keep tabs on one another that range isn't a problem. Just bring binocs as you can determine if the dog stopped on point or is answering a call of nature.
