I don't have any before pictures (just imagine a dirty truck bed with no topper). Found a cap for $100 on craigslist, bought it, painted it with bedliner, and then built my sleeping platform, shelves, storage, and made some mosquito netting screens. I'm in NC, so it doesn't get super cold often (heat is a bigger issue). Fans are a must here, however. I found some cheap ones on the web that you can recharge with a USB charger, as well as a cheap solar panel and converter/ generator (very small, but I don't need much) for under $50.
I have a millard trifold (4") cot size mattress, and it fits perfectly on my platform. It is a bit of a hassle at times to fold it up and shove it to the back, but that thing is COMFORTABLE. Worth the space it takes up IMO. I can slide a board on the right side to accommodate another mattress/ guest, but I like being able to have a little legroom. All cooking gear, tools, etc. are stored away, and the astroturf is a throwback to my first truck ever (used it as a bed liner).
It's not much, but it works for me.
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