marc,
it is important to understand the intended focus and limited resources of
Trisquel itself. Personally I see no big benefit in using XFCE over lets say
LXDE or Gnome in regard to ressources. If you like scripting abilities inside
the file manager you still can stick to Nautilus or use Thunar under LXDE.
Also SpaceFM is a nice option to enhance your desktop experience
(http://spacefm.sourceforge.net/).
If you dislike using Xubuntu because of non-free stuff I suggest you stick to
vanilla Debian with disabled non-free and contrib repos. It will give you a
cleanly working XFCE desktop with no unfree stuff installed.
HTH,
Holger
