If you want a development environment on the tablet, you'll need to add the maemo.org SDK repo; you can get make and a host of other stuff there. It's not entirely safe though, as it's only intended for use on scratchbox, and could conflict with important things on the tablet... use at your own risk. It works for me, though.

I use the shell for getting around the filesystem, mainly, but GPE filemanager is a nice basic one, and EmelFM2 is a big hairy graphical-shell approach, which I'm not persuaded is a wise choice, but is by all accounts good for that sort of thing...