Could try Lee at 281-383-1438. I think his cell is 281-732-2751. I think his company is called Cutting Edge Rv. He is in Baytown TX, probably 1-2 hour drive to Brazoria. He has worked on my Monaco and a buddy of mine as well. He has a shop but started his business by making house calls so for a price I am sure he'd go out there. And he is very familiar with diesel pushers.
I used LemonSquad when I bought mine in Virginia last year. Lemonsquad.com - #1 RV Inspection Company in the Country
They did a pretty decent job with pictures and running through everything. They did not and do not report on the engine or transmission details other than to say it runs fine and shifts fine. They did give me some piece of mind though.