As an aside How about unison?

tar the files onto the DVD and then later off onto a disk working directory to preserve file metadata. Use stat to write filenames and mtimes to a file that lives in a safe place. Run unison or whatever to get the files in sync. Then burn a new DVD only with files from the working directory that have different mtimes than the before snapshot, based on the file with mtimes.

If the two systems support ssh, you can run unison under ssh through dialup. unison is very efficient and only moves the deltas of file data, not usually whole files. It may not be what you'd want but it's worth a look. Better than the sneaker network.
(meaning carrying disks back and forth between computers)