Migration Assistant giving problems ... pull HD as workaround??

So I finally finished cleaning out files on my old MB, installed the Air Migration Assistant and connected via Ethernet and followed all the steps, but it doesn't get very far before popping up a message with "connection problem" or something and then just hanging. Grr.

Yes, I know, lots of people have this problem, and the workaround is to do a Time Machine or SuperDuper backup to a USB drive and migrate from there. But my old MB is a Tiger machine and I don't have a USB drive...

Has anybody tried taking the hard drive out of the old MB, plugging it into a SATA-to-USB cable, and migrating directly from the hard drive?

Dangerous?

Sounds like this might be the fastest way to migrate data to a MB Air?

(and by the way, what's up with there being no Create New Topic button on Apple Forums?)

Because Ethernet doesn't work -- it fails with "connection problem" at random times during the migration. Of course, Apple Store staff just shrugged it off and told me that Migration Assistant hardly ever works -- mind you, this is with a bone stock brand new MacBook Air freshly installed and patched. Grr.

Others have mentioned the idea of cloning the old drive to an external USB drive before, but I don't have a spare HFS-formattable USB drive and would like to avoid buying one just for this purpose.

So anyway, I decided to try it -- pulled the drive out of the old MacBook and plugged it in to a SATA-USB cable, and drive mounted just fine. Oddly, though, the MacBook Air trackpad refused to work when the drive was plugged in -- as in, the motion became crazy jittery and only horizontal. Ooookay, so in goes the USB hub and the mouse to make it work. That worked okay until somewhere in the middle of migration the MacBook Air crashed hard and display went dark and nothing worked, not even caps lock -- only the CPU was busy heating up the planet. Grr. Okay, reinstall OS one more time....

So I guess my trusty SATA-USB cable is somehow incompatible with the MacBook Air. Maybe I'll try taking apart my USB hard drive and swap the internal hard drive with the one from the MacBook and see what happens.

Oh, and, when I plug the APPLE SUPERDRIVE into the MacBook Air, the same trackpad problems result. But after a couple minutes it slowly resolves.

What the heck is wrong with this computer?? *Nothing* seems to work the way it should. Oh and by the way, this is after a logic board replacement last week.