What works for me: I landed on private property twice, this week. Both times I didn't ask. Both times I needed to check out the job site out prior to arriving for crane work. Both times I mentioned over the phone that I'd "stop by" prior to work day, I may have neglected to mention it would be an airplane.

One place was a triangle of waste ground left by the pivot sprinkler system, but right near the house under construction I will be working on Sat. The other was a cut strip of hay field and also right next to the job site. Neither rancher has any problem whatsoever with me doing so. My attitude is if I am going to drive up in a pickup it is OK to fly in. The tricky part of course is knowing when NOT to do it, and it goes without saying don't scare people, crash, or make a lot of noise.
It helps to have a very quiet plane, with big cartoon like tires, with a non threatening name on the cowling, that lands extremely slowly. Both of these customers will be getting aerial photo's of their construction sites at a later date, gratis. Lawyers and releases have never been mentioned in the decades I have been doing this, and I have never been called out on doing it, so I guess I'm doing it right. Living in a very rural area helps a lot. The relaxed nature of the rural residents in my area is why I settled here 35 yrs ago, your area may be different.