1. In my experience they are most vocal dawn and dusk but I have had them poppin off mid day as well. Just kind of depends where in the season the birds are at and if the toms have hens.
2. I've never hunted Klickitat so I'm not sure about bird density. I'd hunt the birds you find even if it's a 4 mile RT unless your comfortable you can find birds elsewhere.
3. The issue with henned Toms, as been discussed in other threads, is they typically don't leave live hens, so the trick would be to cater to the hens and have them lead the toms by you. A few years back I caught up with a tom, jake and 3 hens about 9:30 in the morning. There was a ton of gobbling but they were not leaving the hens. I was able to somehow get the hens interested in my excited yelps and they came to investigate, bringing the tom and jake within range. Got a double that morning both within 25 yards.
Or you could try to circle around in front of their direction of travel and ambush 'em.
Just keep hammering and the pieces will slowly fall into place.
Good Luck.