clean up tight radii
There is always the dremel tool. It is smaller less torque than a trim router and it has a bazillion attachments – including small drum sander attachments. I replaced port Lites on my O’Day 27 this spring. Plywood substrate was in ok condition around the opening. I stiffened it with some west system and clamps. I then cleaned up the opening with the dremel and small drum sander attachment.
You don’t say how large an area you are replacing with laminate or how much substrate you need to replace.
As we all know working on the inside of your boat is like throwing every tool you own and all the material you believe you need or can afford into the trunk of a small car climbing inside, closing the lid and having at it.
Regarding port lites I can’t say enough great things about New Found Metals.