Post 9: top 5 specifications, top 5 contstaints

For my couch/bed in my van conversion, I want to include the following specifications:

Specifications:

1) Ease of Conversion:
The bed must be able to transition into the couch with ease, and vice versa. This is important to me in creating an environment inside of my small van that is stress-free and allows me to spend more time focusing on the aspects of the experience the van is designed for: adventure, camping, spending time in the outdoors, etc. I will challenge myself to allow the conversion to take 5 seconds or less in order for it to be considered a success.
2) Maximization of Function: 
f SPace is going to be the name of the game in this small space, so every square foot must be ulitized to make he most out of it, this will include incorporating things like storage and other utility where ever possible into the build
3) Clean, Minimal Aesthetics:
f Again, small spaces clutter easily. In order to maximize utilize and reduce clutter, a minimal design must be imperative.
4) Longevity:
f I want to build something that lasts. In order to do this, I need to use best-practice woodworking and fabrication techniques, high-quality materials, and select fasteners, joinery, and finishes that are designed to stand the test of time. I want this to last at least five years with no maintenance. Ideally, ten years.
5) Integration With The Rest of The Van:
f the rest of the van will allow me to stay warm, feed myself, store all my gear, and light up the space. this will require another aspect of the build, and I must consider those when designing how this bed will fit into the rest of the build.
Constraints:

1)  Height

The van is not very tall on the inside ( ~46 inches from floor to ceiling). I need to design my seat to allow me to sit comfortably and include adequate storage on the bottom.
2) Time

d I only have a few weeks left to complete the build, so I need to go with a design that is simple enough for that time constraint but also allows me to achieve all of my other goals.

3) Material

I’m going to be constrained to wood most in order to use the tools I have and to match my aesthetic. I will need to consider which fabrication methodologies I should use when working with this medium, e.g., which tools, fasteners, etc.

4) Width
f The van is also quite narrow at approx 61 inches. I plan to make the bed approximately 48 inches, which is larger than a twin but smaller than a full to accommodate one person comfortably or two people if necessary. This will also allow for a foot of space to build cabinetry and other storage items on the side of the bed/couch.

5) Cost
g I don’t want to spend more than a few hundred dollars on this build, which will influence the quality of the wood and finishing I purchase for the build. Fortunatly, interior 1×4,2×4 and plywood should keep me in that range. I will also need to consider that range when selecting upholstery material for the cushions.