job (of) preparing/working

1. We didn’t do as good a job preparing the garden for planting as we should have.

2. She enjoys her job working with local communities.

Q1) Do sentences (1) and (2) mean the following, with the optional preposition "of"?

1a) We didn’t do as good a job (of) preparing the garden for planting as we should have.

2a) She enjoys her job (of) working with local communities.

Q2) Is a comma needed after "job" in both (1) and (2)?

1b) We didn’t do as good a job, preparing the garden for planting, as we should have.

⇒ We didn’t do as good a job, which is preparing the garden for planting, as we should have.

2b) She enjoys her job, working with local communities.

⇒ She enjoys her job, which is working with local communities.