I've done a bit of all of it, foley, design, voice. My most fun piece sound wise was a cigarette boat coming up on the right side of an old river clunker with machine guns (on the Amazon so all the bird sounds) then crosing the bow and going down the left side. Took days and days and sometimes I still see the tracks in my dreams after all these years.
Usually I left all of that to the guys who do it all the time. It was a fun 12 years but frustrating too as it was not lucrative. Still, audio is getting more and more and that's great. It was thrilling for me to see all the podcasts etc. My first show was done on tape... can you imagine? (Yeah, I'm an older fart)