Using Arduino as Laplink interface?

I have an old laptop I want to save files off but here's a few problems:
hard drive is SCSI and SCSI to IDE converter is a couple hundred dollars plus finding 2.5" SCSI to 3.5" SCSI adapter would take time if it even exists:
no floppy drive
no CD burner and software for CD burner typically comes on CD but without driver, laptop can't see CD anyway so installing won't work
no USB
Laptop is pre-WWW era so no browser or internet connection
no Ethernet support

A dock on eBay is going over $200 shipped and are UNTESTED!! Only 1 tested and working dock on eBay and seller clown wants $500 for it.

I do have a laplink cable that has RS-422 on one side and a spider of RS-422, RS323 (both 25 and 9 pin connectors) and I think 485? I however don't have any computer that has serial port and local place has USB to serial adapters starting at $25. I'd rather avoid this since it'd be used only once.

Can I use Arduino somehow as a middle man for connecting legacy serial port on my laptop to USB port on my computer? My laptop does have ZTerm program (Macintosh version of Hyperterminal) that can be used for direct serial to serial connection. I have an UNO R2 with socketed chip I can remove to make it a dumb USB to serial adapter or leave Arduino for intelligent conversion. I also have Mega 2560 and Nano but chip are not socketed.

Or can I somehow use the Mega as SCSI to USB adapter? Wiring up 60 wires would take a while (50 wires for standard SCSI-1 plus power and ID setting)

Forget about all the other stuff, buy the USB to serial adapter and use that laplink cable, especially if you already have experience with it.
If you want to get your Arduino talking to that machine you probably spend more than the 25 bucks for the additional hardware needed (BTW, USB to serial adapter are available for under $10), let alone the dozens of hours you would have to spend with no guarantee that you will succeed.