I agree the leak could be from a lot of places. I had a 5SFE camry that leaked from the valve cover (back side), oil pressure sender, main seal and the oil pump o-ring. I thought it was the pan gasket also but once I had the other leaks fixed (except main seal) the leaks were greatly reduced.
The oil pump o-ring was the main culprit, so if you have a big leak from the front of the engine just inside the right front tire, that could be your problem.
Get some engine cleaner and the hose and clean everything up under the hood, it makes finding the leak much easier.
I think you just have to take off the down-pipe to get the oil pan off, I tried to get the bolts off up near the manifold but they were hard to reach and very tight. I'm glad I gave up as the pan gasket was not the problem.