I'm in the same situation, I have 2 2wd 4r100's and have been weighing the options. Still don't have a plan as to which rout I'm going to go. I purchased a 4wd tailshaft and a cast steel 4wd tailshaft adapter. After reading through this I hope I purchased the right parts.
Just stopping by to state, I enjoy your videos. Not many 4x4 van adventurists on you tube. most people who enjoy your videos will never say anything, only the people who don't will tell you.
Once I build a swing out, I'll mount my plates to the outside of the box. Add a small light and I will be in compliance, no reason for the law to hassle me.
The real question... how much more money would you make finishing the van vs selling as is? Now subtract for your labor and materials needed, then add extra for unexpected costs. Is it worth putting in the extra labor and materials for something your not going to use? If the profit margins is...
When doing a partial 4wd swap, do you reuse the stock rear driveshaft? At this point, I believe I'll be doing the partial swap first, then coming back to the transmission/transfercase once I can afford a quality rebuild.