I have some changes planned but not yet made that will reduce it to just two.  The idea is to make config always a plist, with standardized keys for arg0 and env.   Quasiquotes make plists easy to construct.  Then all we need is spawn and spawn-path, and likewise with exec and exec-path.  There are a few other changes I have notes on but not yet edited in.  Expect draft #6 fairly soon.