Hi Phil,
So far so good👍
If the remaining paint is sound then leave it.
Sanding any further may start weakening the hull where the wood is already exposed.
Ask me how I know 🤔
Resin: If you are going to resin the hull then don't hold back, do the whole thing.
Go the whole 'packet of rashers' 😁
If you just cover the bare wood then you'll end up with a patchy surface which will haunt you all through the painting and finishing process!
As far as colour scheme is concerned you have choices depending on which pennant number you want to model and where she served.
White in the Med, e.g. Malta, use white primer as well, black in home waters; e.g. Inverness, with standard grey primer. See attached pics.
You're right about the starboard door - should be a ladder!
Have fun, cheers, Doug 😎
http://www.rafboats.co.uk/rttl2.html