We have written an R package client to the Concept Library API, which allows you to connect and download content directly into data frames in R.
Downloading and installing the R package
External: the package is available on Github and can be installed using the install_github() function in devtools. This will automatically download and install dependencies, like installing from CRAN.
Using devtools to install ConceptLibraryClient from Github
install.packages("devtools");
library(devtools);
install_github("DSThayer/concept-library-client", subdir="ConceptLibraryClient");