It's perhaps worth pointing out that those weren't core modules in 5.8.x.
To me, it sounds like the OP is targetting a wide range of installations, trying to settle on the "lowest common denominator". So there might be 5.8 installations among them.
In other words, in order to not have the program die with "Can't locate Module/Load.pm in @INC ..." on 5.8 installations, the OP would have to first check the classic "built-in" way, i.e. BEGIN { eval {require Module::Load; 1} or ...}, if the module itself is available — and depending on the outcome, possibly do the loading of the other non-core modules the same classic way...
Just a thought.
