My approach to finding places to hunt has been spent scouting public land. I begin with a surface ownership map, then a satellite photo review. I generally score a good place less than 30% of the time, or it takes me a couple of trips to a mediocre place to figure out how to hunt it well. I will often have a place that is stellar become mediocre or the opposite occurs due to changes in grazing, fire, or land management. I've gotten very particular about sharing a hunting place due to the effort it takes to find a decent one and how quickly they can change.
Hunting a reservation only location has always seemed distasteful to me. Some birds thrive in agriculture, especially with good cover adjacent to it. If you want big success hunting pheasant, then you just can't get away from it. However, this doesn't mean you need to pay some club or organization fees to hunt worn out land. Your premise of knocking on doors has significant merit. I generally drop off a gift like you suggest if they allow me access. For me, the pursuit of a good hunting place is a bit of an adventure and paying for it takes something away from the pleasure of the experience.