Seeing as I have one too I will pipe in here. Mine has next to no rust in it compared to some getting around in the mountains (think missing wheel arches), but little brown surface spots on the underbody where stones have nicked the paint. There are a few spots in the doors that seem to have a little repair work done in them for rust, and another in the boot just next to the key hole. Those look like common spots. The actual structure of the car seems pretty resilient to rust from the others I have seen, with the exception of the arches.
Oh, they seem to have a leak prone boot though, after the rainy season mine had accumulated a small puddle in the spare wheel alcove. Throwing a a container of water sucking salt goodness in there kept it dry after that.
Just an update on the Alto. Been running great but the CV's are pretty bad so they need done as soon as. The Skyline is due to be ready in 2 to 3 weeks so I'll drop the Alto in when its ready. Plan is the refurb the CV's as they only come as a whole driveshaft. I "might" get a few other things done while its in, thinking maybe the intercooler. A few pics from today: