Welcome! And congrats on retirement. Work is not all it is cracked up to be, and a self motivated person will find more than enough to stay busy. Many happy and healthy years!
I own a Sprinter and will probably get another one when the time is right. First two points. A wise uncle once told me "never buy a Mercedes because you think it will be cheaper". I think this advice continues to be true. Second, Mercedes has been selling trucks the world around since before many of us were born. You can find a place to get them serviced in Timbuktu.
Here is proof from my formative years of growing up herding goats in the African colonies.
People are attracted to Sprinters for the performance and space the unmodified van body offers. If someone is purchasing a unit built on a cab and frame I am not sure why they would go with a Sprinter. I am sure they have their reasons, but I would not do it. It seems like you get all of the downsides and none of the upsides.
Similarly I don't really trust the Sprinter as a 4x4 off road platform.
We like our Sprinter because we use it as a multi-purpose vehicle. Sometimes seating 7 people and sometimes just my wife and I traveling.
Wow, never heard that one about the rats and mice! That is a new one for me. We park in a wooded lot with many mice around and have not had that issue. Hard to keep them out of the attic, but nothing in the Sprinter so far!