Back in 1989 and aged 23, I simply walked into the entrance of Petra, Jordan; paid my fee, and wandered in with sleeping bag under arm. Despite a sign saying no overnight stays, no camping – no one stopped me.
I spent 3 nights sleeping in a small cave/tomb away from the main areas. Leaving my backpack there, while I explored by day.
My bed was a mattress of swat, deep-rooted bushes – that I could not pull out but sawed thru the stems with my Swiss Army knife; the clumped heap on the stone cave floor was quite comfortable.
All meals consisted of processed cheese with tomatoes and tinned tuna in Arabic flat bread that I carried in with me. Supplemented by sweet, hot tea – “shay” offered by local Bedouin (who lived within the ruins).