That's about it Phantom. What you should do is run a defrag on the drive you want to put your swap file on first which will also prevent fragmentation. Just remember that you also don't want the drive to be used very heavily by other applications either. You will have to weigh up the pro's and con's and take it from there.

Of course if you really want to get technical you can also make sure that your swap file is located on the outside of the platter of the hard drive instead of the inside because data is transferred to and from the drive faster at the outer edges but that's another whole kettle of worms.