Not really, you would need backing plates and stands to do it. Aside from the git-rot idea, this one is by far the most difficult.
I think you're over-thinking the situation some, this really isn't a big deal.
All you need to do is remove the affected area, just a little cut off wheel would do the trick so nice it's almost sad.
Surface prep the bottom side of the laminate, trowel on some product, have your core strips ready, I would suggest nothing really wider than 8 inches (6 would be ideal). Now you could do this one of two ways, if you think you are up to it, strip the core sheets lengthwise, now you have a four foot strip that's ready to play. Toss a rubbermaid (or some other brand) plastic trashcan down where you will be working - making sure it is on its side, prop up some shims so it doesn't roll around on you, and now you have the perfect table to wet out your core material. Scrim side down the core will open up all of its kerfs so that you can coat everything with resin (probably the reason the condition of the old core is so bad, proper resin penetration didn't occur). Now that you have a nice soggy mess, pick it up with your double (or triple) gloved hands and starting at the end with your non-dominant hand holding the core, slide your dominant one along the length to bed the strip into the compound on the top, having your hand nice and flat and don't be afraid to push (if you want to do that breathing your wife learned how to do, go ahead. no judging here). It might take you a little bit to learn how much resin is too much resin (damned gravity) and how much is just right, it's easy to reclaim excess resin from your strip just by putting down a plastic paint tray (or one with a liner, or even both - just watch out for exotherming - know enough when to step away from the project and let it kick. Better to do a little grinding than get into a serious problem.)
Once your strip is in place, go over it with a stout bubble buster or some other instrument.
a laminate roller might work for this job as well, you can really put some pressure behind it if need be.
But remember, you're only displacing the bedding material and making it one with the resin infused core, you want to get the bedding material up into the kerfs as much as possible without destroying that connection. A nice even pressure does the best job, you don't have to try to kill it.
Now that you have your first strip in place grab another and repeat the process. It will take a little bit to get the pace down but it's really simple once things are going. Trowel an area for two and a half strips, put them in place all the way across, do another area with the trowel, more strips, trowel, strip, etc etc. Mix up small batches, that way you can walk away whenever you feel like it (your back will let you know when that is, trust me). No doubt you will get some bedding compound to peek up between your strips or even the kerfs themselves - this is easy to fix. You could say "fahgettaboutit" and just touch them up with a grinder when you prep the area for the interior fiberglass. You could swipe your finger along the seams (using the back of your finger like a squeegee). Or you could just take your roller and roll them over and hot coat the back side of your core at the same time (that's what I would do).
Be sure to stagger your joints on the strips, easy enough to do, just cut the skrim and make your strips shorter/longer. Don't worry about little voids on the corners of your curved radius on the trunk top, cabin, wherever you're coring. A little bedding compound as a filler after you are all done is the simple easy way to solve this, pound it right in there. Pretend it owes you money and you're here to collect.
This is a big daunting project that is hella easy if you just take a step back and consider things for a few moments. Having a pair of helping hands would be fantastic, be that a small child, an understanding wife, or even a parent figure who is willing to help out. They can mix product and apply resin to your strips as you're fighting the gravity of the situation.
- Small batches are your friend
- Always have a backup set of tools (gloves, roller covers, anger management classes, etc)
- Know when to walk away, take a step back, remember to breathe (hee hee hee - hooooo)
- Wear your safety gear (glasses - most important, probably a hat, some old clothes that you don't care about, gloves - glorious gloves and multiple layers won't hurt you one bit, you can shuck them off and keep going to slap a new pair on much easier than you would with sweaty fingers)
- Proper ventilation (those big 20" square fans work wonders, pump that stuff outta there)
- Have fun. If you can't have fun doing this project then you are doing it wrong.