I just picked up a sundancer with a single 454. The timing cover was rusted through and while I am there I should install a roller timing set . The engine is stock and I am looking for an inexpensive quality timing set and cover

inexpensive and quality are 2 words that dont belong togeather,if you want quality buy a cloyes timing set and an edelbrock aluminum timing cover,if you want cheep i dont know that answer because i dont go that route.

I agree with mike. I have the edelbrock aluminum covers and like them.

Timing cover rusted through? What's the rest of the engine looking like ?

The circ. pump is probably leaking. That's what caused the timing cover to rust through. Be sure to check/replace the pump.
Eddie