Any fixes? Doors poor fit, hard to close.

[I1502]

I'm suppose this is a common post, but search didn't help.
My 87 LB doors don't fit well, especially the gap between door and lower body. I also really have to slam them to close all the way. This is not a worn-out truck, but a low mile one owner.
I remember in the past that 73-87's close tough and sounded tinny. When they first came out in 73, my boss bought a new one and I started driving his old truck, a 67. One rainy day, I opened the door to the 73 and got drenched, and I thought "how dumb...no rain gutters on the top of the doors". GM soon added the bolt-on gutters.
Any way to solve the problems?
Thanks!