If I were just putting my Lisa in the car to take to some show, I don't think I'd take too many precautions. Probably just put a blanket or towel over the tube to keep it from getting scratched and buckle it into the back seat. Unless yours has been sitting in the sun for the past 30 years, the plastics in the Lisa are very good quality, a far cry from the plastics in late 68000 and early PowerPC Macs.
If you've got a Profile you're taking with you, I'd probably treat it the same way, just make sure your disk has seeked into the landing zone before transport.
If you've got a working Widget, that's probably where I'd get some kind of padded case. I've read enough threads here and on 68kmla; Widgets use a glass indexing platter that's glued into place and if that platter ever detaches from your Widget, good luck getting it to work ever again.