Ranger School does not make anyone a Ranger.
If you want Ranger school, then try and enlist with a Ranger 68W contract, or apply for RIP while in AIT.
Then after 68W AIT, you attend RIP, an 8 week pre Ranger course used to select new members of the Ranger regiment.
Then you would attend the 27 week Phase l of the SF medical course.
If you pass that, you are assigned to the Ranger regiment.,
Then in 6 months to a year, you will be sent to Ranger School.
2, If you go to a regular unit as a 68W, it will be very hard to get into Ranger School, you would most likely have to reenlist to get your command to give you a slot.
3. No, you will not have alot of time to take college class's, maybe one online class each semester.
NOTE: 68W is not a wheeled mechanic
68W is Healthcare Specialist