I am contemplating running the engine without the valve cover to try to find the problem noise. I know I have to have some sort of cover over the top cam gear so as not to roostertail oil everywhere, but are there any other issues I need to address to do this, or am I way off base considering doing it?

 

I'm not sure about Toyota..

but Ive seen people adjust valves on a sbc like that..

 

I've seen people take an old valve cover, cut holes out of the top, and use that as a temp splash guard while you adjust/diagnose the valves through the holes.