I like to run light Window Managers, like Fluxbox, not for performance just because I find them simpler to configure and they fit better my working style. But having automatic hardware and network detection is also very convenient.
Is there any way I can have that same Gnome or KDE functionality without having to use the whole environment itself?
Yes, install components of gnome/kde and/or lightweight alternates.
For networking, take a look at wicd
What do you want in terms of hardware detection ? If you want a graphical interface for installation of graphical drivers (nvidia) you can try jocky or jocky-gtk. The graphical drivers tend to be a one-time installation so not sure if you want these tools.
There are tons of other small applications such as tint2, nitrogen, pcmanfm, etc.
On Fluxbox / openbox you can install single gnome / kde applications
See :
http://blog.bodhizazen.com/linux/a-5-minute-guide-to-fluxbox/
https://wiki.archlinux.org/index.php/Lightweight_Applications
