I won't address the issue of RASP 2 and SFAS being up to chance because I am not to that point yet. But I can tell you all about OCS because I just did it about a year ago.
First thing when you talk to a recruiter take a hard no stance on enlisting, because they will ask you about 12 times why you would be willing to enlist. If you want to "Paint walls" as the current CSM of IBOLC puts it, than enlist. If you want to have the great honor to lead soldiers, than become an officer. The process for an OCS packet depending on when you start can take anywhere from 3-9 months. You can't really game this because it is based on board dates. If you are not an idiot you will pass the board. Your main focus should be passing Ranger school, you will be told that Basic is hard, it is not. You will be told that OCS is hard, it is not on the federal side. You will pass IBOLC just fine if you don't heat cat. Than unless you spent all that time preparing, Ranger school will fuck you up. This aspect comes into play later.
Second, basic is easy if you are not a shit bag; even than it is pretty easy. Your MOS will be 09S, so everyone will know your are an officer candidate, hopefully you go to Benning because you will actually learn Infantry shit. 09S's attend basic combat training, not OSUT (what you will call "Infantry Basic"). When you get to OCS having attended at Ft. Benning will give you a huge leg up. No less than 12 candidates in my class from Ft. Jackson never rucked before attending OCS, and then they had to cope with the climate. I grew up in the Pacific NW, when I arrived at Benning in April I don't think I stopped sweeting for at least 3 days. "Drink Water!" is something you will hear everyday multiple times for the 10-12 months you will be there. Get someone to mail you a ranger handbook in basic. They will take this from you at 30th AG (Hell), but most BCTs support you having one.
When you get to OCS you will be split into one of 3-4 companies, C-co being the worst. You will have to take a PT test, and based on the results roughly 100 candidates will class up. the rest will be held over. DO NOT forgo classing up because you are "not as prepared as you want." Average cut off between the 4 classes I interacted with as they fed into IBOLC was 265 PT Score, you need a 300. This goes back to preparing for Ranger instead of OCS. If you want Infantry you have 2 pathways to get it. The First is the Order of Merits List (OML) around week 9/14 they will pull each person in the company 1 by one into a room where they will be allowed to pick their branch. Only a certain number of slots will be allotted for each branch. My class had 14 Infantry slots. That includes all the branch details. That initial PT test you take is averaged with the final test before Graduation, and bears the second highest weight of any evaluation in the course. The other event that you want to crush is Patrols/OPORDS (Operations Orders) I recommend the book "Get Tabbed" by Bronston Clough. Not plugging for him, but he breaks down the patrol process Barney style, no need to memorize it but it will give you leg up in OCS.
The other method to Branch infantry is to drop a packet towards the beginning of the course. The cadre will go through this process sometime in week one of two. These packets pull from the same allotment as the OML so you should put one of these in. The current BN CMD for OCS will rightly, not approve a packet that has a lower than 290 initial PT score. Also you will want at least 3 letters of rec concerning specifically why you should be an Infantry officer. These can be the same from you OCS app packet, but they need to concern the specific branch you want. You should get these before you attend Basic, just to prevent any friction in timings. The 14 guys in my class that got infantry excluding myself ( I got Lucky) were easily the 13 best non prior service soldiers in our company. They where excellent in every area of the course and they took it seriously despite how easy it was.
The final and most important piece of advice, go out of your way to find, befriend, and learn from the prior service folks, especially those from the SOF community or the infantry. The most I learned more from now 2LT. Pankow, about soldiering in 12 weeks than I have learned everywhere else in my life. Along with him was a former LRRC Squad leader, a 1st CAV IN Team leader, and a PSYOPs guy. No matter how much you read, train, or prepare, you will know nothing compared to these guys. Seek them out to learn as much as you can.
Assuming you get IN and go to IBOLC. OCS and IBOLC are right across the street from each other. They eat at the same defac. The difference is that you will not live in a barracks, and you will likely have more experience than the ROTC guys. Don't take this as a point of pride, some of them will smoke the dog shit out of you. Your commissioning date and class up date will likely be separated by 2-6 months. This is where you will get attacked by complacency, which if you seriously want to go to SOF you cannot afford. Attempt to Walk on to every class up, until you make it. The OML for IBOLC doesn't matter. It does not effect your duty station or follow on schools. Obviously don't fail anything and work hard, but execute the course violently. Sitting in snow bird PLT (Hold under) for 6 months waiting to class up will fuck your timeline, and you will likely be in worse physical shape.
IBOLC and Gym time is a crap shoot. Fortunately Ranger school doesn't give a fuck about your Bench max. Do pushups every other day until you can no longer push, than do 49 more. In IBOLC you will run a lot, just maintain this going into holdover at the end. When I left Benning they started a program where they sent 3-4 LTs to SURT (Small Unit Ranger Tactics) if you can pass RAP week I highly recommend taking this route. The pass rate out of SURT is much higher than IBOLCs and they focus on slightly different things. This will give you the best chance to Pass Ranger School coming out the gate.
Note: The PT test is changing so you should be aiming to get a 550-560 PT score.
