I also call the Parks and Wildlife field officers that handle the area I'm looking at as well as the forest rangers. Most of the time I have gotten helpful information.
I've also found that getting to know the Parks and Wildlife field officers can really pay off. I always call the particular field officer for the area where I archery hunt, and tell them my basic plans, what truck i'm driving and where I'm parking, if I have anybody else with me, even tell them where I'm planning on setting up camp and general hunting area. It develops a level of trust that you're not poaching, and have even gotten text messages during the season from them of where they are seeing/hearing bulls bugle.
Along with all the tools you mentioned, I also get the Trail Guide book about the area. Typically the authors are a bit more on the granola side, but the information has been excellent. They will do reviews of the various trails that weave through the area you're looking at and pass on information... the new area I'm currently researching has a large creek running next to the trail, and the trail crosses over the creek several times. The trail guide pointed out that one of the bridges washed out in an avalanche back in the mid 2000's and there are no plans to fix it so you have to ford the creek.
Also will do a bunch of google searches to try and see if there are any outfitters in the area i'm looking at, and any that I find, I call and act like a potential costumer and ask how many other guys will be in camp.
Never used hunting fool, but if it costs money I doubt I'll ever consider it. But also curious to see if anybody considers the fee worth while.
I've never found a resource outside of the field officers that give information such as hunting pressure or antler genetics. But Colorado (not sure about other states) does post quite a bit of draw and harvest statistics that you can get a general feel for how much pressure a particular unit, or group of units, get. Although it does not help for any particular smaller area within a unit.
Like most backpack hunters, I typically rely on distance to separate from the crowds.