[obican]

If your slides are already in slide carriers, projector+dslr method is pretty fast. You get to scan as fast as you can click on the projector and the quality is quite acceptable. Otherwise, if you can't get your scanner to work, probably the easiest and fastest way is buying another scanner, using it and selling it afterwards. 

 

Macro rig requires a lot of fiddling at start but when you set one up, it'll be both fast and good quality, especially if you stitch.