Oh, wait, there is no path. So to get ready for entry-level PvP you need to lose or get carried through random BGs until you have enough honor to buy gear, one piece at a time. It would be like gearing up for heroics only off the JP you get from clearing a normal instance. While having a debuff that makes you take 20-30% more damage than everyone else.
Yeah, cause everyone on the other team magically gets full PVP gear while you have to slowly earn it one piece at a time.
Wait, no, they don't - they have to earn their gear battle by battle one piece at a time too.
So in your example the mobs in heroics would have to earn their gear by killing and looting players - I recall how much easier the Lich King was to fight before that one guild chain wiped on him and he got all those epic drops and became so much tougher to kill. ;-P
The path to gearing up for PvP is called "leveling" - you run BGs as you level and save up your points so that by the time you hit whatever the cap is you've got enough points to buy a few decent pieces - it's not all that sophisticated a concept, especially with everyone and their mom dressed head to toe in heirloom gear now a days.