Yeah, for a mom-and-pop shop, but not for any sizeable airline wtih detailed SOP and diverse operation. Most airlines have their way of doing things - from the moment you arrive to the crew room, through flying the aircraft to the moment you leave the crew room after duty. To suggest you could learn this in 3 days (PC + 2 days of line training), is... optimistic.
Where I work, you'd be looking at a good 2 months, assuming everything goes according to plan and there is plenty of training capacity available.