With Software Manager, Synaptic, or in a terminal with aptitude or apt-get and the proper options, install xfce4 first, then remove cinnamon with the same tools after you have made sure that you have logged off, chosen Xfce as your session and made sure that Thunar, xfburn, Abiword, Gnumeric and the other Xfce specific applications are all installed before you remove the cinnamon package.
If you don't check on the proper installation and operation of Xfce before removing Cinnamon, then I hope you are comfortable working for a while from the command line to fix everything up.
As for all of the 'Mint Goodies', you may want to install mate-desktop before installing xfce4 to ensure the version of the goodies matches better than the Cinnamon desktop (incompatible versions of GTK). Again, check your work, and keep a copy of a Live installation medium to help recover from mistakes and keep them from being disasters.
LMDE Mate 64-bit, LM17 Mate 64-bit
Debian Xfce 64-bit, Xubuntu 14.10 64-bit, Xubuntu 14.04 64-bit, Antergos Xfce 64-bit, PCLinuxOS LXDE 64-bit