My rig was a public transit van with wheelchair lift. The lift had problems that could not be easily fixed and they tell me the cost to get the specially certified technician to do the work was going to be more than the value of the van. I bought it for $650 knowing it needed a lot of other work.
My generous BIL and nephew did the work to take out the VERY heavy iron pieces. I actually got to sell that off and made a few hundred off the metal and the passenger seats that were unbolted from the floor.
I was not on hand for the ripping out, but I did hear from them that it was a lot of physical work. Not anything too complicated (other than the electrical disconnects mentioned above), but a LOT of muscle required on the commercial grade heavy pieces.
Here are some very different things to watch for or consider, depending on if your lift van is a custom-made commercial rig:
1. My "passenger" front door is a public bus type door, meaning it has a very heavy swing arm that the driver must release and push out in order for the door to open. This takes a lot of room up front because of the movement area. Plus, you cannot enter using that door unless it has been left standing open (and beware that a strong wind the wrong direction can blow it shut). One day I'd love to look into having a regular RV door put on, but I suspect the cost might be more than would make sense for the shape my rig is in.
2. That same door has a stiff "brush" bottom that lets a lot of "daylight" through. The good news is that I never really worry about ventilation when I cook inside. LOL I camped at only one place that had a mouse problem, but that door not sealing up was like a welcome gate for them.
3. The two barn doors added to the side of the van to contain the lift were horribly designed. They lean back from the bottom to the top. From all the use, they no longer align perfectly but even if they did the angle might still be a problem. When it rains, I get an indoor "water wall." LOL My solution was to string 505 cord across the top inside and hang a regular cheap shower curtain from that. I keep it pulled back for driving and viewing out the windows, but have to remember to pull it across if there is a chance of rain and I'm parked. The water does seem to run out at the bottom (showing the bottom is not sealed all that well either).
All that being said, my rig has tremendous headroom inside --- a 6'3" man can stand up without scraping the ceiling in the middle. It is roomy for a van yet it fits in a parking space like a Tundra-sized truck would.
So my advice is look at HOW the modifications were made to any lift van you consider to see how they might impact the living space in unusual ways. I'll keep my van until the reliable motor gives out or the rust creates a sinkhole (half kidding).
