I don't know about the valve covers, but in reference to changing plugs and wires:
I just removed the decorative plastic cover on the engine and the distributor housing (which required unplugging it) and I was able to reach the rear spark plugs. It was very tight and it took a lot of patience but I was able to do it within 2 hours. The OE plugs were VERY tight but I was able to change them out successfully. Along with the new wires. A lot of the work just takes patience and care.
I don't really know if that helps you at all but that is my only experience with it.