If you want to get rid of the barrel jack you can drill out the input jack hole with normal wood drill bits. When you have the hole to the proper size you will need to use a plastic or metal jack plate and drill pilot holes for the jack plate mounting screws. I use the Puretone input jacks. Check out youtube videos to help with this.
I didn't catch a picture of the outside of the input jack but if there is no jack plate then you have one of the barrel jacks. I would address that as well while you're changing everything else out.