Each individual would be free to enter into a security contract with one of many security organizations for his protection.
This individual would go about his business trying to make money to earn a living in order to afford to pay for a security organization to protect him while he slept, or to protect his home while he was out doing business.
Now it is possible that all of the contracts could just be verbal and done with a mere handshake.
I suppose one definition of a conservative libertarian would be someone who believed that he could read people well enough that he never needed written contracts. He would either enter into a verbal contract, or he wouldn't enter into any type of contract with a particular person.
Still one would expect that a practical libertarian who found himself living in a highly non-libertarian world demand written contracts.
A person who calls himself a conservative libertarian who would enter into a mere verbal contract with a woman to share living space, expenses, and the care and upkeep of children seems to be an oxymoron.
And who would enforce a broken contract? A contractor hired to arbitrate this broken contract? And who would arbitrate that broken contract? And so on, ad infinitum.
But the real, central, glaring error of libertarianism is the libertarian notion of rights. If rights are unalienable then they must be eternal. An eternal lawgiver (God) is the only possible source of eternal rights.
It is logically impossible for God to will evil. Therefore, no one possesses an absolute right to do evil. No one enjoys an absolute right to intoxication, fornication, adultery, blasphemy, etc. Man may, for prudential reasons, be permitted by the State/society to participate in these evils without State imposed punishment, but he never enjoys a God-given right to do evil.