The main part of the existing layout of my ASTRO-VAN is the variable bed-frame (see more at ipernity.com/doc/stargazer95050/47262742 .
That size determines the rest of the available space. The cabinets on the passenger side are useful, but they do limit the storage. Compared to my 1st ASTRO VAN, where I could transport wide boxes next to the bedframe this is a big change.
It turned out that these boxes became too heavy to load or transport and now, I divide & conquer ==> e.g. store smaller items in these cabinets can be beneficial but they are an obstacle to storing multiple bikes.

This Divide & Conquer strategy also means, I need to find room to store multiple, smaller bags or boxes. And there are other factors -- some of which seem fixed but are worth reconsidering :


STORAGE -- bicycle. As shown in this photo, transporting one bike inside the new van's cabin is possible, as long as the mattress isn't wider than ~80cm. Transporting two bikes would require them to be partly disassembled. In both cases, you must remove the bike(s) to access the cabinets or storage you have underneath the bed.
Alternative : it is possible to add an external bike-rack -- this new van has the necessary hitch at the rear bumper. That, of course, limits your access via the rear doors while carrying bikes. And you have to protect the bike(s) from the harsh elements, vandals & thieves.

STORAGE -- below the bed : currently clear space offers only ~25cm/10" in height and this can be sufficient for items like surf boards (prev. owner was a surfer). For trips to Burning Man, I have used large, flat boxes to protect clothes & food from the dust. Those fit underneath that frame, but you cannot stack them. EVEN WORSE, my astronomy equipment and ice coolers are taller and don't fit beneath it.
That (low) cargo height allows for a comfortable position to sit on the bed without bumping your head. That's the trade-off of raising to provide storage for larger items -- hanging the bed from the ceiling really avoided many of these issues.
The insulation in the new van further lowered the ceiling compared to the original Astro van.


STORAGE -- raising the bed by max 10 inches : that's adding a lot of extra storage space below the bed frame but removing 10" of headroom also makes it a lot less comfortable to sit. I like the idea of using the cabinet as a table for keyboard & laptop and have the monitor semi-permanently placed there. If the bed is too high, the position isn't comfortable. Currently, I think ~45cm/17" height is large enough for my equipment -- raising it by bed by 5", max 7 inches.

The mechanics of raising the bed & mattress that high are another serious issue that I have started tackling. Below you see a setup to test the modifications and evaluate the changes. It illustrates the possible changes (7" raise) and allows to compare different options.