People still want to go AD because most of her ratios are ad. I say go ap and cdr. Machete into trailblazer into Magus. Rush sorc shoes during this period. Nuke for 1/3 of peoples hp until they build magic resist (still during this period). Buy void staff, chunk for 1/4-1/3 of hp at this point. Buy rab cap. chunk for 1/2 hp. Buy will of ancients so you can heal while underground. Itemize accordingly.
Gameplay? Clear buff camps, back at lvl 3 (start gromp if you can, otherwise get golems first). Grab trailblazer, clear chicken camp for ward clear, visit closest pushed lane. If all lanes are pushing to enemy instead of tower, head to wolves for more exp. If not, ganking lanes goes like this:
Burrow mode through jungle of opponent via tunnel. Use Q within enemy jungle to snipe at enemy laner (thats how long the range is). If they keep fighting your team, keep sniping. If they head to you, tunnel back out. Obviously for this double tunnel, you will need to chill for either your tunnel to come back up OR for your CD in tunnel skill to reset. Rinse and repeat until your lanes push themselves. Your Q has 100% ratio and morgana range, does aoe of about 100 units. Max it at lvl 9. Once team has sufficiently pushed itself because you acted as an extra support/ward for your team (yes, I consider AP rek a support jungler because ad makes her too squishy), join teamfights by being far away from enemy team. Continue sniping tactics you used in ganks. By now you should literally be chunking the enemy champions so hard that they are trying to hunt YOU down. Use yourself as bait. Very effective with your free flash, especially if you preset the zone you were baiting too. I did this in a team builder or draft.
TL;DR? Go ap, pure ap in the jungle. Ignore your jungle minions for the most part, only clearing during buffs or chickens. Rush Magus and Sorc shoes. Rush rab if they dont buy magic resist to counter your ridiculous ganking presence (not power yet, thats at level 9), otherwise rush last whisper (yes rush each item, dont buy in pieces). Its gimmicky, but incredibly dangerous. You don't need ad damage at all. Your purpose is to pressure the enemy team off your team, not to hero mode 1v5.
Of course, this is my opinion. Take with a grain of salt, offer hatred of my idea if you wish. Constructive criticism is appreciated, counter speculation without prior testing of what I have done as well is not as much. =)