20 VM Desktop Conversion

sudo apt-get update
sudo apt-get install xfce4 xorg

For a more refined desktop environment, try

sudo apt-get install --no-install-recommends xubuntu-desktop

replace xubuntu- with ubuntu-, lubuntu-, or other preferred desktop enviornment
the --no-install-recommends eliminates additional applications, removing it will add a word processor, a browser, and lots of other applications included in the default operating system.

Reinstall Virtual Box additions for better integration adding X/mouse support

sudo mount /dev/cdrom /mnt
sudo /mnt/VBoxLinuxAdditions.run
sudo umount /mnt

wget http://download1.rstudio.org/rstudio-0.97.551-amd64.deb
apt-get install libjpeg621
dpkg -i rstudio-*
rm rstudio-*