Just want to also mention, the skin is fiberglass. I know the comment about Bondo means well but not certain that is a proper product to use on fiberglass... unless you know it is. I have been surfing all of my life, yes I now live in CO, but point is I've done a lot of fiberglass/resin work and to keep things waterproof, make sure the proper materials are being used. The only problem I see with repairing the current cracks is the waveiness from the previous leaking will never go away unless it is replaced... and that includes using Eternabond.
I actually have used this to fill in a hole in my exterior fiberglass skin
Sun Cure 4.4 Oz. Fiberfill Repair Kit and it works great. This will not separate from the fiberglass skin and will be permanent. I do keep a tube of this in my TT. When it cures, it is more opaque and it will need to be sanded to be smooth but it is great stuff for fiberglass.
If you do the repair, non-replacement style repair, you could always get a sheet of diamondplate, form it with a curve and attach it to the top to cover everything up. With an added new metal seal on the bottom and using the existing metal seal at the top along with new dicor, it may end up looking OEM.
I love me some land yachting