Camry V6 engine oil leak on exhaust

[airmechanic]

Hi; My first post and my 92 V6 with 65k miles has leak not fixed completely by replacing valve cover seals and gaskets (which were hard & leaking) Leak appears to be possibly camshaft seals or front crankshaft seal. Is this a frequent failure mode. My wife is growing tired of the burning oil smell and now I share her displeasure. It's approaching time for belt replacement and what else can leak in this area which is accessable when replacing belt and above mentioned seals.
Thanks for any assistance