I wholeheartedly encourage you to create your vision...
I have an Organic farm outside Portland, Oregon with a 'Guest House' an 'Airstream' and a Glamping unit called 'The Bali House'. I do not host weddings, but I do offer the property for retreats and events.
https://airbnb.com/h/thebalihouse
https://airbnb.com/h/guesthouseatcrookedfingerfarms
https://airbnb.com/h/new-luxury-airstream
I have been operating the property successfully for over eight years, so I have a lot trials and errors under my belt!
Here are some things that come readily to mind:
Make sure you are operating as an 'Organic' farm. (Not necessary to be certified).
Wedding venue insurance is extremely expensive!
So...hopefully, you have very good farm insurance that will allow you to have vacation rentals on the farm as well as events. (Most won't).
The unit in the photo is very high end with the decor to match... Keep in mind that your initial investment will be significant!
Figuring that you have someone handy that can build you a platform deck, you are looking at around 3K just for the wood unless you have a mill.
You will also want to invest in a really good mattress and luxury cotton bedding, etc. I offer my guests big fluffy towels, slippers and robes.
I would strongly suggest you go with a King size bed if you can fit it in...
But be aware that the bedding/ mattress and canvas tent will mildew. You will need to be able to replace it all on a regular basis. (And those white Ikea chair cushions will be trashed by the first guest).
Also, if you are off grid, cleaning any kid of carpet to super host status is not doable without a generator.
I don't know what your bathroom/water situation is, but as you mentioned, 'primitive' bathrooms... they aren't really 'glamping' and don't appeal to a lot of people. Unless your property is so amazing that people come because you have a waterfall in your backyard...
Outdoor showers are cool and all, but unless you are in Hawaii or Bali, they really aren't all that fun!
I would consider adding a private hot tub or some kind of bathtub inside the unit.There are systems that don't require electricity. But again, all this is costly...
So in short, not to dissuade you, but what you are proposing would require at least a 30k a year return to make it profitable.
You might want to consider starting out with tent sites instead...Bali House sleeping loft
Also I agree Robin4 that you should look into Glamping Hub... Most of my bookings come from them.
And there is a new invitation only sight called Yonder: https://www.yonder.com/
That is looking good for us.
Best of luck to you.
Cheers,
Kristin