Syncing Aperture between Macs
RSync the library from the one system to the other when you're at home. It's network efficient, only transfers updated files, and is designed with exactly this sort of thing in mind. It's also free, and installed by default on OSX. It's a command-line tool, as long as you're happy with that sort of thing. It'll keep the libraries in sync quite happily, and syncs both ways.

You'll want something like:

rsync -avh --progress --delete /path/to/source /path/to/target

Depends on whether you mount the remote drive locally, or use an rsync daemon.

Nice instructions here: Software to synchronize two directories (local/remote)