Landscape Photography Income

I was hoping to get a discussion started on making money with landscape photography. For anyone who is willing to share their experiences:

-What has been your most profitable source of income?
-What source of income do you enjoy the most?
-Which source isn’t worth the hassle?
-What source is the most efficient in terms of the time you have to put into it?
-What was the most uncommon way you made money off landscape photography?

Personally, I work full time outside the field of photography, so the side income I make is to fund photo trips and supported charities I care about. Given that I have a full-time job, I’ve been exploring different ways to make passive income so that I can spend as much of my free time as possible on actually taking photos, meaning that something like print or digital sales work well, but scheduling something like a contracted shoot can have its limitation due to my schedule.

Curious to hear what everyone’s experiences have been with this!