Caret doparallel in Rmarkdown: Missing verbose info when using render()

This may produce what you're looking for, adapted from here, it essentially replicates when you use the knit button in rstudio, which produces the verbose from train, however using this method you should be able to pass in parameters to render. Just change the path to the wd of your rmd file

owd = setwd("path/to/your-Rmd-directory")
system2("Rscript", c("-e", shQuote("library(rmarkdown); render('test.Rmd')"),
            system2("html", "test.html"),