To implement OO or not in R package, and if so, how to structure it?
Did you read this? https://cran.r-project.org/doc/contrib/Leisch-CreatingPackages.pdf Maybe it could give you some insight in how to create package.
That resource is ~9 years old. There are more modern treatments available. You can read mine at http://r-pkgs.had.co.nz. Hadley