Here in the northeast, A Pt hourly with their CDL can drive in feeders during free periods in Summer and Fall, complete their 30 day probation and be eligible for a bid without having to complete another 30 (article 57 New England supplement), and a lot of 6:1 opportunities go to those employees.
To me it all depends on where you live. First thing would be to get your CDL. UPS could be hiring feeder drivers off the street near you but with no experience... It’d be difficult for you to get the Job. With your CDL, work towards a package driver job. Then when you go full time, reach out to feeders about opportunities. They’ll pull you out since you have the license already. Research your local as well. Your local could offer CDL training. You could also use the tuition reimbursement that ups offers to PT hourlies to go to a tractor trailer school. I have a 24 year old feeder driver that did this. He used the tuition reimbursement to pay the school, he contacted me, during Christmas I trained him and now he has a FT feeder bid less than a year after starting with UPS.