Is there any kind of operating system on it now, e.g. DOS, Win95? You might be able to (a) copy the key win98 files onto a Zip 250 disk, and then (b) hook up a serial port zip250 to the laptop and install from it. (Or for that matter, a zip 100 would work, you would just have to use a couple of disks and copy onto the laptop's HD.)
An external tape drive that works through the serial port might be another option. Or, a serial port LS120 could do. Or, one of those CD drives that works through a serial port.
Of course, you've then got the challenge of first getting the zip or tape drivers and software onto the laptop. A program like PCMag's slice32 might do the trick. Or, you could download the drivers off the web onto your laptop (e.g. get Iomegaware from the Iomega web site.)
And, a really really really tedious approach would be to just copy stuff onto floppies and then copy it onto the laptop.
Zip drives are cheap and ubiquitous, so if you can't use some of the other solutions (e.g. network) that have been suggested then a zip drive may be the way to go.
But in general, if you can get an external serial port storage device that will work on both your laptop and on a machine that has a cdrom, you can probably pull this off without too much trouble.