Well since you are replacing the gaskets, it is a lot easier to do the headliner. I did mine with the glass out. I had the shop that did my seats and door panels kind of make one for me. They sewed up the material for the curves and left lots of extra material around the edges. I glued the headliner around the edges of the cab and used the trim around the doors to hold it in place until it dried (see pic), then cut the excess off and had the glass shop carefully put the windshield in. I did the back window as they are pretty easy to get in and out, I used 2 screwdrivers but you can also use the string around the gasket trick also.