The idea is as old as the world: when space is limited, it's strategic to make environments "double faced" . Then there are bathrooms that turn into shower stalls, desks and counters that turn into beds, lockers with variable volumes, folding beds to make room for bikes, etc.
First of all, an example: the classic double dining room that transforms into a double bed . After a few minutes, the transformation is complete: tables and sofas by day, mattresses by night. Just lower the table and place it between the two benches, widen the seats, reposition the cushions to create the mattress, make the bed. 5 minutes and it's ready. Same operations in the morning to restore the dining room. Would you do these procedures every evening and every morning during your 20-day vacation? Would you mind not having a dining room as one uses it as a bed (unless there is a second dining room)? When it's raining or when someone wants to relax and someone else wants to use the computer, consider: What compromises are unacceptable to you?
I've known very happy and very relaxed people who have changed and repurposed everything in a 6-foot van over the years, but I also know people who don't want to hear about it, except in exceptional circumstances.
The same thing happens in some bathrooms: swiveling toilets (shower or something else) to drain the shower tray, folding sinks or swivel walls to create an insulated shower tray, and shower without getting the fixtures, mirrors, and fixtures wet. cabinets. In some cases the solutions are really convincing.
The upside of convertible is given by great campers where everything has a place and doesn't share it. Then there is the toilet and sink on one side of the corridor, bathrooms with shower cabins on the other , sailor double beds at the back, twin beds with wardrobes underneath.
What I can express is my point of view , as the choice is always purely personal and all the choices considered are considered correct .
I love air, light and space : I avoid very low lofts, beds tucked between closets and closets, large spaces without windows.
I always try to keep the beds ready for normal crew at all times, avoid conversions. The only exception is the pull-out bed (typical, but not exclusive to caravans), which is simple to lower and raise, can stay built and therefore can be used quickly. But when open it should at least partially free the dining room and not hinder the use of the cell door.
Every bed should have a window next to it , the porthole usually above it for up and down doors is in good condition.
Normal and useful bathroom with or without separate shower
Always available dining room, knee room, deep seating (I like to sit cross-legged) and ease of access
With these features (crew of 4 people) I have had caravans between 6.99 and 7.30 meters, caravans with overhead cabins or caravans.
I would also consider a van for two people but definitely not "short", I like to have the right space (less is better), I don't worry about air and light, exterior size and parking