Do you have a link to scheme that is made and approved by cryptographer, that i am able to do with pen and paper and would require 2 of 4 parts? I would be more than happy to use that, but I have not been able to find it.
Secret sharing schemes usually involve mathematics (and not just simple calculations).
You can do every scheme with pen and paper, altough it is not
that easy.
Sharing schemes based on the chinese remainder theorem aren't that hard to calculate with pen and paper (and a calculator maybe).
Take a look at
Mignotte's and Asmuth-Bloom's sharing schemes. There is even an example on wikipedia on how to split and retrieve the secret.
You can definitely do them without a computer. However using a small (even self-written) script which implements that scheme should be fine too from a security-related point of view. But then, i don't know what your thread model is and why you want to do it with pen/paper only.