I need to document that better, but rmpk ships with a "ROI optimizer". ROI is an R package that provides bindings to most of the popular solvers: https://roi.r-forge.r-project.org
But I am also working on providing custom bindings to different solvers, to be able to have more control over them. E.g. GLPK: https://github.com/r-opt/GLPKoptimizer
Thanks for your effort. You've already covered some ground in the examples, at this stage you're trying to fire up network effects and attract users/analysts/developers.
Treating this like an optimization problem, it seems that there's more potential for attracting users if you broaden the scope of vignettes and let Duckduckgo/Bing/Google do its magic for queries like 'optimum scheduling in R' or 'cutting stock in R' etc etc.