I wanted a simple package to automate documentation of R libraries in Sublime Text 3 using roxygen. I couldn't get R-Box to work, so I just took this function from Rtools and turned it into a package that works with ST3.
Just clone this repo into your Sublime Text 3/Packages folder. For me this is located at ~/Library/Application Support/Sublime Text 3/Packages/.
git clone git@github.com:explodecomputer/ST3roxygen.git
To insert documentation, when the cursor is on the function line press cmd + alt + shift + r.