Just my opinion from what I have seen over 35 years.
I have seen them come off the roost as early as 10 minutes before technical daylight, like you can only see well 50 yards or so. Usually start to roost in late evening, say 30 minutes to dark. Some things to remember., If there was severe weather over night, they may already be on the ground (blown out). Often in Spring, Toms will gobble from the roost to get feedback location from a hen, then will fly as close as possible to her (why I am out set up before daylight) I have had them land with-in 10 yards before. Common when there is strong competition.
I like decoys, only have been using them for about 10 years, but still have taken more tom's without one. In many situations I think they can make the difference.
Being new property, you may try hunting the edges of the pecan orchard, they turkey seen, may winter there more than hang out during Spring. If it is in a bottom, or low area, might try finding openings on a hill, or elevated terrain. Rio's can and will cover a lot of acreage in a day.
As far as calling, 9/10 times, less is more. One thing you can do effectively with a mouth call, is add emotion to the sound, making a "I'm lost! save me" yelp, can often pull in the hens with tom in tow, or will get a tom to commit when he really doesn't want too. Hard to explain on a keyboard, but think how you would sound if this happened..
1 Your small child falls down and gets hurt, you rush over and say something like "Oh you poor baby, come to daddy"..
2 Your small child disobeys you, "come here right now young man!" Of the 2, which would motivate you to "go" in the same situation.
Half the fun is figuring them out, so you and the nephew are already into enjoying the fun, when it happens, it will become an addiction.
Friends don't let Friends drink and post.......
The first 5 day's after the weekend, are the hardest....