How to set custom directory for installation of R packages

How do I set a custom directory to install R packages? Is it simply the following?

install.packages(c("data.table", "tidyverse"), destdir = "C:/Users/stackinator/Documents/R-libraries") 

I’m not sure if my slashes are in the right direction (Windows 7) and does my destination directory need to be in quotes?

I know I can setup this in my .Renviron file, but I’m more concerend with individual package(s) for this question.