Cleaning up asian mill/drill

Well, my desktop mill-drill now works! Yesterday I did my first bit of
actual 3-axis CNC cutting with it, and it all seems to be to scale and
the servos and E-stop and dump-circuit and limits all work as they
should... so I'm happy. The first project was prepping a faceplate for
the casing of the mill, and I should do the backplate for the casing
on Friday. So, very soon it'll be closed up and done.

Which brings me to question: What do you think is the next most
important thing to do?

I suppose I have to resolve the backlash on the Z-axis (Dan Mauch sent
me a doc on fixing this), but what about lapping the ways? Will
lapping improve it any? Replacing the gib-bolts with anti-loosening
ones? I know I'll have to do ball-screws eventually, but I think I'm
going to wait just a little bit on what will be a very timely and
costly procedure (not to mention the fear!) What other improvements
can I make to the mill-drill to make it truer, more aligned/etc. I
seem to have quite a bit of backlash on X/Y, is there any
none-ballscrew way to get this down? What else can you personally
attest to adjusting?

Thanks!
(BTW> And please don't reply "Get a bridgeport instead".. I know.. I
know.. I just can't fit a "quality" machine in my living-room :)

~Abby