The executable below is a simple aid to calculating rough times to complete a walk in the hills. It is based on my own rough experience, and although it takes something from Naismith's rules, it is not a copy of these. Additionally it attempts to take into account weather and terrain conditions. You may want to download the readme file that goes with the program. Unfortunately, although I am a Mac fan, I had to write this for the PC! Hopefully I will get around to writing a Mac version at some stage!
There is also a Java version below that will run in any enabled browser (versions 3 and above, Mac as well as PC!). If you download the zipped version and unzip it, loading the mountain.htm file into a Java enabled browser will allow you to run this version off line.
Java version