Looks a bit too oily to actually determine where the oil leak is. I would pressure wash or degrease the engine clean as step 1. However, seeing what I see, my guess is the rocker arm cover gaskets. Often, the valve covers don't have the valve cover hold down tabs as they get lost or thrown away. Check these out so you can see what I am talking about
They come in different sizes and chrome if buying aftermarket. These tabs spread out the clamping force under the bolts used to tighten the valve cover. When they are not used, the bolt is tightened down and it can distort/pinch the valve cover points at the bolt rather than provide a good even clamping.
If you do not have these this is what I would get first. Get the correct sized one for your valve cover bolts. Longer is better if you are OK with some of the chrome ones or simply paint over them. Then pull the valve covers and look at the holes where the hold down bolts go. These need to be flat. If they have been over tightened, they will be dimpled and are only pulling down at that point and not really clamping down on the valve cover gasket. If this is happening, the oil can seep right under the gasket because it is not being clamped effectively. I usually turn the valve cover upside down, find a flat surface to support the valve cover edge/lip, and take a hammer to it and gently tap it flat again.
I have no recommendation on gasket material as some are cork and some rubber and I have used both. You just want to make sure they are not some kind of "Made in China" thin paper gasket material. FelPro is usually a good brand.
The leak at the rear could also be from the valve cover gaskets or even from the distributor hole. Never had a problem with the distributor hole, but there is supposed to be a thin paper gasket under the distributor - so look around the base of your distributor And the intake as well.
My next suggestion would be to go to your local auto parts store and get an oil leak detection kit. It will include a liquid dye you add to the oil which will show up under a UV light. Never used one, but never had the need for one either, but if I did have a stubborn oil leak, I think this is the way to go. They are not too expensive. Hope that helps.