The 75th is arguably the most physically fit unit in ARSOF. I am always impressed with the 75th guys I meet, and their achievements on the battlefield are unparalleled.
RASP will go easier for anyone who is absolutely crushing their APFT. Run your ass off and get that time down to 13:00. It isn't a requirement, but you will be better off. Work hard at your pull-ups as much as possible, and do not kip-up or any of that CROSSFIT pull-up/chin-up crap. When they test the pull-ups, you will start from a dead hang, and you will pull all the way up and lower all the way down for a rep to count. The pushups you are doing need to be good ones as well. Practice your push ups by going all the way to the ground and lifting your hands up off the ground before pushing back up as well. The APFT is changing, so that is a benefit, but that also teaches you to actually go all the way down. I would try to slap that chest to the ground if I were you, because as a grader, there is no doubt when someone is doing that. I know what the Army PT manual says, but I think it is solid advice to get the pushups as close to the ground as possible. You will see a lot of people doing bullshit push-ups in AIT, and sometime they will get counted on the APFT. This will not be the case at RASP. You will need to be doing good push-ups, good pull-ups, and running fast.
I don't want to give you the wrong idea either. Memorize the Ranger Creed starting right now and start learning some knots as well. GROG Knots app is pretty good. If you are a GT 142, most everything else shouldn't be a problem as long as you aren't terrible at land nav.