I'd also run the hard drive manufacturer's own diagnostic, assuming that the system comes with a drive and also assuming that such a diagnostic exists. For IBM/Hitachi (HGST) drives, there's DFT (Drive Fitness Test). For Seagate (and some Maxtor) drives use SeaTools. Fujitsu drives can be checked with FJDT. I believe that there are others but these are the three that I use most often. I would also suggest using the DOS versions of these programs as they do not depend upon a working install of Windows. These diagnostics typically will come as bootable floppy disks, however some are directly available from the drive maker as CD images.
Other than that, I think that you have most of the bases covered. Be sure to run the Interactive tests in PC Doctor. These are the ones which require your input (i.e., pressing all of the keys to see if they work, moving the trackpoint around, etc.) or your visual or audio attention (video and speaker tests). Most of the systems in the laptop can be checked with PC Doctor just by itself; however some diagnostics require additional hardware for complete coverage. For example, the parallel and serial port tests (the R40 doesn't have a built-in serial port so this doesn't apply) usually only check internal signal paths - they don't check to see if the signals are actually getting in and out of the connector(s). For these "loopback" tests, a special plug is required that connects the input and output pins together so that the diagnostic is able to check this signal path. If you don't/can't run these loopback tests, then about the only way to check the ports would be to install an operating system and connect some hardware to the laptop and see if it works. This particularly applies to the PCMCIA and USB ports as PC Doctor has a shortfall in those tests (there's a loopback cable for those ports but I've never seen one).
ref:
http://www.hitachigst.com/hdd/support/download.htm (Drive Fitness test download is about halfway down the page)
ref:
http://www.seagate.com/www/en-us/suppor ... s/seatools
ref:
http://www.fujitsu.com/us/services/comp ... ities.html