Hello all!

Headliners are easy but messy to repair yourself.
Any large fabric store will have "foam backed headliner material". You
will want a striped solid color that matches as closely to what you
have, though to be fully original you might want to go one shade darker.
They may even have 3M Headliner Adhesive. Be sure to use the 3M; it
works, others don't.
I paid about 20 bucks for the material, and 10 for the adhesive. It
looks great.
Tips: depending on your car, you may have to remove or loosen a fair
amount of trim. Try to do it when warm, and remember that our plastic is
kinda brittle after all these years.
Get the whole headliner out with fabric attached.
Outdoors, remove the old fabric, and then use a scrub brush to gently
remove as much of the old deteriorated foam as possible. Do it out doors
because the old foam is sticky and dirty.
Now that the headliner backer board is as clean as you can get it,
prepare the new material. Make sure to have a bit extra....
Spray the backer board with the adhesive. You want good coverage, but
not too heavy. 1/3 to 1/2 the can for a full size liner, much less for a
T-top car.
It helps to have a helper to lay the new material on. Lay the material
onto the adhesive without stretching it too much. A tiny bit of stretch
keeps it smooth, too much makes it peel off. Wrap the edges behind the
board, then trim to about an inch over. Spray more adhesive on the back
edge, and press the overlap into it.
Now let it dry for a few hours.
Hey, a new headliner!
The visors can be done as well. The edges are tucked into a groove in
the front edge and sides, and the mirror assembly in the visor can be
pried out. Use rubbing alcohol after pulling the fabric off and brushing
off the majority of the old foam to prepare the surface for a good bond.
The only real catch is that the raised plastic trim piece on the top of
the mirror assembly is glued on, and you have to VERY carefully break
the trim free with a tiny pry tool used under the edge, while not
breaking the rectangular trim piece... I found it can be done, but it is
tough. Optionally, don't mess with the mirror assembly, just pull the
whole thing and recover the visor itself.
Other than the above tips, recover the visor in the same way as the
headliner.

Hope this helps!