I know, you have to make a calculated decision of course.
I see what you mean now, and it was my fault for being inaccurate. I did not mean the NPOR was anywhere you could make a stance, free from everything. I was trying to say that you find the NPOR where you can take a stance and not be affected by the cart path. That place might be inside the tree, but that's luck of the draw (or fade). The NPOR is the closest spot where you can take your stance with a normal ball position using the club you would use for the next shot, and be free of the cart path. There might be a rock, tree or bush on that place.
A quick example: You hit the ball onto a cart path on the right side of the fairway. The NPOR for you is on the right side of the cart path, which is littered with thick bushes, giving you no place to drop and no place to stand. Dropping the ball into the bushes is obviously stupid, so you have to make a decision. You can deem the ball unplayable, go back and hit a new ball, being penalized with distance and a stroke. You can drop the ball inside two club-lengths with the penalty of one shot, which means you can drop it on the left side of the cart path (fairway). Or you can hit the ball from the cart path. You get relief from the cart path, but that option is not possible because of the bushes.
If you take a drop with penalty, I assume you can drop the ball onto the cart path, perhaps hoping it will roll to a better position. If you do drop the ball from an unplayable lie and it rolls to the left side of the path, making the NPOR on the left side, can you invoke the rule for immovable obstruction and drop it onto the fairway from there?
Can the ball always roll up to two club-lengths from where it first touched the ground? Regardless of which rule you apply? Which means that if you want to take a drop from an unplayable lie, drop it two club-lengths from the oiriginal position, it can roll another two, moving the ball up to 5 yards from where it originally lay. It requires a sloped area of course. In the event of relief, the ball can roll up to 3 club-lengths from the NPOR. I have myself re-dropped a ball because it rolled outside the designated drop area of the two club-lengths, which is wrong.