Unable? Unwilling? Sometimes it is hard to find which is the true story!
Seems there are a good number of folks who see an RV an assume they know nothing.
But then there may be lots of things I don't know about why they might not be able.
So do they give any reasons for not being able?
It looks like a pretty standard 2 din opening but are the camera inputs confusing the issue?
For info, there are single din and double din and that is just the standard for "single high or double high" . Not a high tech thing, just part of the standard language in auto radios! Possibly need to look to larger shops with a wider experience range?
Shopping to find the right radio may need a closer look to match what you want and what you have.
SE Pa is a wide area but this pops up as a place that seems they would understand?? Their display LOOKS like they would like to sell you something!
Good luck on that idea, though!