I’m thinking if you have no problem now,just run it. Unless the guy you know or someone he highly recommends, I personally wouldn’t trust any shop unless you have a really good recommendation. Too many ripoff artist and too many that do more damage then you go in for. I have a recall on my truck...
Not sure if yours is the same but my 1200 norcold goes thru a defrost cycle every I believe 28 hrs or something and the temp will rise. I try to start it so the 28hrs (don’t hold me to that time) happens at night when it’s cooler out.
You should try it on a 40 foot motor home.. thing weighs a ton.. you did real well on your van. I had a high top years ago and loved it and would like to get another one day.From the pics it looks like practically brand new and for 5 k it would probably cost 50k plus for a new one. Best of luck...