av8nmech,
You're welcome to come check out BSD anytime, I live in Parker and work at Roxborough State Park in Littleton, and I even make it out to Buckley every once in a while since I have a RV spot out there.
I wish there was another diesel classic Bronco along the front range that I knew about, I would have loved to check it out before I started mine. There are a couple of 4BT swaps along the front range for sure, off the top of my head I know of a full size diesel Bronco in CO. 4btSwaps.com is a good starting point to get information on all sorts of diesel swaps, including the Isuzu motor, but I find their forum difficult to navigate and information isn't well organized.
I am extremely happy with my swap, I love driving it daily and at +20 mpg it's cheaper than my F150. I'll say that I still need to add some sound proofing to the firewall, cowl and floor pans to make it a bit more comfortable on the ears. I recently spent 4 days in it scouting for my upcoming hunting seasons and I was wearing foam ear plugs 100% of the time by day 2.
There is a good source of 4bt motors now that all of the hostess vans went to auction a few months back, but their price is a little up there. I would look at buying one that has been frame cut from the firewall forward or buying the entire truck, and make sure it's a P pump motor with a charged air cooler (CAC or commonly known as a intercooler). Most P pumped motors are later model motors that have been rebuilt within the last 10 years or so. Don't look for a "bargin" rotary pump motor from the 80's unless it has a documented recent rebuild. You can always go to:
https://quickserve.cummins.com/info/index.html and check out the history of the motor with a SN or CPL.
I won't be much help with the Isuzu motor, look to the web for that, I didn't dig into that option since I had a line on a 4bt.
You'll need to solve more than the motor with a swap, the transmission and likely transfer case will need to be swapped out. You'll need to be able to solve fitment issues and fabricate up mounts and brackets. I'll hazard a guess and say I have 1000 hours of labor into mine just to get it back on the street, of course I also lengthened it a bit and I'm still working on the back doors and top.