Needing advice for black tank issue

I did not think of the large portable tank possibility. With that, I would be able to open it up and get a high pressure hose in through the dump valve and try to break it down from the other side. I did try contacting a holding tank service, but due to liability, they will not pump or vacuum out of an RV tank, hense the 40 gal buddy tank that they will pump out of. I seriously appreciate your suggestions on that. As for a professional rv tank cleaner service, we are rural, and have none in the area and my only option for that is to haul the trailer into the city and to an RV service facility where they can do it. Being that I live in it, am rural and have pets, hauling it into a service yard will take some planning and why I am doing all I can think of to fix the issue within my means. All the suggestions though have my brain thinking and giving me other idea's, so I really appreciate all your suggestions.