1st of all, i got a basic keyboard and mouse, so anyone can do it.
Go to Input Binding.
Change sprint to Shift+W(The key you use to run.)
Apply.
To make it work, you need to hold Shift+W. Then, you release shift and W at last.
Now, you are suppose to be able to sprint without holding anything, but W.
If you open Gui mode, loot a grave, you will have to toggle sprint again. This is the annoying part, but better then holding right click in my opinion.