Been playing around running TWM on an old Toshiba Qosmio. It's on top of a Slackware 14 install, all the package groups apart from KDE, KDEi, XFCE and XAP.
The twmrc was built around a twmrc file I found at:
My own one is attached to this post.
A lot of it I stripped out (particularly all the remote access stuff) but it was really useful to work from as the menu structures are all there for you to see and I managed to create my own menu structure from that. Obviously they are all related to software that I have installed but you can easily replace/rewrite sections as you see fit. Also, a lot of the menu items have geometry/positional flags added that suit my screen so you will probably want to play around with them.
I haven't delved in to all the mouse/keyboard related stuff in the twmrc yet, but it's an ongoing project. I've not yet sussed out a way to open the menu via the keyboard yet which I would like to do.
Other tweaks I have made come in the various config files such as .bashrc, .Xdefaults, .xpdfrc, .elinks etc... aliases to shell commands and appearance alterations to GUIs