You are right, it wasn't easy and sometimes there was a lot of friction between me and my wife, but everything turn out to be good.
Because we did everything ourselves, if anything goes wrong I'll know exactly where to look and how to fix it.
For instance I know now that building the floor from the panels was a bad idea. It was better to make it from solid sheet of linoleum or simmilar material. Also the chargers - I installed six of them and I overwhelmed the van's charging system. Four is the safe limit, so I had to disconnect two. Other than that everything seams to be fine. I already traveled to Deadhorse, AK and to Key West, FL and in few days we start new trip in our finally finished van.
For those who have no time here is a 5 minutes video: