Which gives me a higher chance to go active duty, dropping a 368 packet or through SMP?

It depends on what kind of timeline you are looking at and what you want to do. Whether you want to do a single tour on active duty or make it a career, take a look at the different career paths and options available for you. Do you want to work towards a degree now full time or do it after duty at night, or after a tour on active duty? As was mentioned you need to talk to a recruiter about what the current business rules / options are for a reservist going active (there are a few different ways), and to the ROTC ROO about the current accession process, other requirements and how Airborne and Air Assault schools work now. It would be easier to go active enlisted as you are already trained and in the system vs going through ROTC where you would need to go through the screening, selection, accession and training process. There is nothing wrong with either path, I helped many reservists go active while doing a tour in recruiting, while I ended up joining ROTC about a year after IET.

PFC Hartanto I would say that going SMP is always a good option but it will not give you an advantage in competing for an Active Duty slot. If you would like to go the Officer route I would highly encourage going SMP while taking part in ROTC. Now even with the short amount of time that I have been Active Duty I can tell you that the OML has changed for competing for slots. I would get a hold of the ROO, at whatever school you plan on going to, and see how the new system works. If you want to get an Active Duty slot I know it depends on a few factors (again there might be some new requirements): GPA, APFT Score, Volunteer, Extra Curricula's, Performance at different positions within your ROTC Battalion, and Branch of choice. If you are going for one of the "sexier" branches, like Armor or Infantry, it becomes even more competitive for an Active Duty slot. Take into account as well that there are options to sign for an ADSO. While you are taking part in ROTC you can actually compete for Airborne and Air Assault slots while you are in the program. Obviously it all depends on funding and slot availability but the option is still there. What school do you plan on going to?

If you want to go Regular Army check with your nearest recruiter. S/he will tell you the current business rules which governs prior service accession into the regular army. And like SHT Brainard stated, don't waste your or other people's time/effort doing SMP unless you really want to become an officer.