Bandera

Racing 'cross is one of the best ways to develop bike handling skills, being able to do clean mounts/dis-mounts and put out the effort doesn't require much in way of dedicated equipment.

Join a local cycling club, get a coach and have at it. A club tends to move "obsolescent" perfectly serviceable equipment thorough the membership as those obsessed by "the latest thing" buy into it and sell off the "pervious thing". A good way to kit yourself out at a discount.

Yes, clipless pedals and shoes do make a difference in road racing performance, safety and control. Essential I'd say.
In Cat5 upgrade gear as you can and don't be intimidated by the guy on the shiny Team Tinkoff Replica, it's not about the hardware and never has been.

-Bandera