finish season w/ half iron distance

I have done many years of racing at international distance tris and have been successful. I have a few olympic races left, but was hoping to end the season doing a half. My focus is to race competatively at the international distance for the reminder of the season so the half would be more of a "c" race to simply see how I like the distance. I will have an olympic distance race which is an "a" race for me two weeks before the half. Any thoughts on when or how often to get higher milage without destroying my international distance racing? What would be the low end of longer rides and runs I might be able to do, but still not die during a half. Current high milage for bike is 45 miles and for run is 9 -10 miles (obvioulsy this is not weekly numbers). Thanks for your tips/help.