I finally decided to tackle this project after taking some time to research and think about how I was going to go about it. Just like a lot of other people, I REALLY wanted access to that extra space below that floor and I can tell you now, it was totally worth the effort and money. I can fit all kinds of stuff in there and the hatch is concealed to any would be robbers under my mattress. I've been outfitting my van geared towards a roadtripper style with simplicity and low weight in mind. No built in platforms, kitchens, or other comforts, as I like space in the back when I am relaxing on the road, so this extra room created without taking away space, was invaluable.
Here are the photos I took as the project went along.
Starting with the floor and front support already removed.
The concept here was to be able to use some existing bolts and threads to tie everything together.
I cut the center support out but left the posts. Sawzall with a metal cutting blade worked well.
I cut and shaped the sides of the cargo floor out to form the bridge to the posts.
Also cut and shaped the front support, then reinstalled as shown.