I want to respond out of an abundance of love for what Paul is doing and has done. Also,approach it from a sustainable business perspective. I look very much forward to Paul telling me my idea sucks.
and it might.
I'd imagine a current issue is that Permaculture, especially as practiced at the Lab, attracts people at an arc of their life where they are looking to build a career and not pull in money from people who are established and have more capital. "Normies" that might pay for experiences rather than education. The people that could pay and fund the people Paul is training to do this at their already established homes. I'd describe it as building a pipeline from Normie to Full died in the wool Permie Warriors.
My idea I'd call PermiBNB. You mention the rural nature the property as a hindrance to people coming out, but there is already a market for that in short term rentals like AirBnB. So to make it economical that it would be building out a small section of property with cabin like structures for vacationing people to experience different levels of ecological buildings. Maybe they'd be interested in the events and activities at the Lab and maybe not, perhaps they'd just want a quiet place to enjoy time away.
To fund, and prevent the death by obligation, I'd say there would be structures demonstrating different levels on the Wheaton Eco Scale making initial investment possible at a lower level of eco scale. The funding would be a kick starter and the incentive for the kick starter would be actual credits to stay in the finished structure. So, like a gym membership the obligation is satisfied simply by the thing existing and basically being pre booked. Like gym memberships I imagine many people would never cash in their credit to stay or would hold onto them for coming years leaving plenty of room for other renters to stay there. The overhead of an AirBNB is lower than other activities, there is already business models for this to work and would allow people to experience Pauls genius without him actually having to add excessively to the workload. Each kickstarter could be filmed as stretch goal but no video provided to backers. A video about the build could then be produced as an additional kick starter that would be simply to fund the editing. A class could be held about the build as an addition income stream but since it's funded outside of the kickstarter the lack of participation isn't going to kill the idea.
In the end you could end up with some good ongoing passive income for the Lab, showcase the ideas, upgrade and evolve and give people the opportunity to experience the ideas in a lower commitment level. A weekend of staying in a place with a RMH for example just to try it out.
Slots could be blocked to provide space for people to stay there at larger events. Small family friendly events could be planned, like pick and cook your own dinner night.
I'm not someone who would come out to be a boot, or even take a class, I have a great job, a side business, a family. But I'd love to support the work and experience the ideas you are coming up with. I'm sure there is a larger market in the ecological AirBnB than in the actual interest in spending money on videos, classes or other direct lines of revenue. I'm sure even someone without any idea what it is you are doing would enjoy a stay and likely get excited about it building out a pipeline to future classes, videos, books ect.
In a bit more crass way of putting it, Get rich people who like to pretend they are Paul's to pay for the actual Paul by trying out the paul way of doing it's finished products.