Well....
You should be able to put the hard drive from your A1200 in it, and that's about it. It can use PCMCIA, so 4MB slow RAM is available there, or some other dongly interface like a Squirrel (instead, not at the same time). You might replace its 68000 with a 68010 for a useful speed boost. Anything the A600 can do the A1200 does better and faster. An A500 is more expandable, and an A500+ also offers ECS. The lack of an expansion slot cripples the A600. It doesn't even have a full keyboard. And the original power supply is too weak to cope with an external floppy. It's a doorstop, imo.