I'm a prospective Coast Guard Reserve enlistee with a pending boot camp date of Jan. 4.  I have not yet signed my contract.  My ultimate goal is to become a USCG Officer.  It would be a dream come true.  From the research I've done, it seems there is only one path to a commission for an enlisted reservist. OCS.

As far as I can tell PPEP is only available to ACTIVE DUTY service members, and not RESERVISTS.

I'm also working on an engineering degree. I'll have my A.S. Engineering before I leave for bootcamp.  My recruiter said I'd be eligible for Direct Commission with an associates of engineering, but the USCG.mil website says otherwise.  It said there's a 4 year ACTIVE duty requirement, and the bachelor's degree will be made mandatory soon.

How is a reservist to become an officer. Is a bachelor's and OCS the only way?

As a reservist you do not apply through the OCS program, you apply through the SRDC program. I do not have the recruiter manual in front of me so I do not have chapter and verse on PPEP for reserves. Cooch, Gears, any info off the top of your heads? (I am at a conference). An associates will not get you a reserve officer slot as a bachelors is required.