Yes you could get there

but beware of the bumpy road ahead of you.
If you want to save both disk space and memory footprint, you could try disabling some fonts in xorg. That has helped me before. Just like loki99 recommended, blackbox or fluxbox is a good choice for a lightweight window manager, add abiword/gnumeric/koffice instead of OOo and you'll be good to go.
If you go for koffice, that'll need kdelibs and if you go for abiword, you'll need gnome/gtk libs. I won't say which one is bigger than the other

but you should pick one set of libs and stick to it if you're real short on disk space.
Rémi