I cant help you with the Skyraider but adding a catapult & arrestor hook is pretty easy.
Add the following to the aircraft cfg.
[launch_assistance]
launch_bar_pivot = 21.88, 0.00, -3.94
launch_bar_lug = 23.6, 0.00, -5.54
[Tailhook]
tailhook_position = -15.70, 0.00, -0.60 //-17.50, 0.00, -0.60
tailhook_length = 8.00 // 8.0
cable_force_adjust = 0.50
Now these numbers wont help much, they are for the Aerosoft F14 but the way I modify my planes is I will create a Red light & use the above as the starting point. Then I will move the location of the light so that it matches where the hook & cat hookup are on the plane. Once they are postioned correctly right change the numbers above to match where your light is & the hook I can almost grantee will work fine. You will probably have to play with the cat by moving it forward or back to get it to launch right. If the cat is chucking the plane up move it forward. If its nosing it down move it back.