Just a bit of self serving here, but try Catalina - Capri - 25s International Association
This is the association for the Catalina 25 (and 250, and Capri 25). If you have your heart set on a Catalina 25 (and I can see why), the association (I don't think it's wrong me plugging it here since I have no financial interest in it) holds manuals, tips, tricks, and repair information all in one place. Joining the association is inexpensive (I think $22/year), and gets your discounts at major retailers, and insurance, as well as signs you up for the Catalina Mainsheet magazine (again I make no money on this).
Keel smiles are a COMMON problem with the fixed keel Catalina 25, but purchase should be with the knowledge that there are extreme examples, that should not be considered... You can search the forum on the association without joining and see what extremes they get to. Without realizing that there is a ton of work to get them right again, this could be a deal breaker for you if you aren't up to the work.
The cabin sole is a cosmetic problem, I wouldn't worry about, except if it came from LOTS of standing water. Which would lead to water laying on the keel bolts (rust perhaps)... The keel is bolted through a solid fiberglass keel support, and you'd be able to see the heads and get an idea how much standing water has been in there... rebedding keel bolts is a lot of work as well.
When you say soft core, I think you mean deck? That I'd run screaming from. That's just me, but I'd rather not have to cut out large portions of deck and have to reglass.
A fellow association member just did as you suggest, bought a boat that needed a ton of work (and there is nothing wrong with it, if you plan on a year or so before you splash)... and he also purchased a "spare" for parts, essentially making one boat from 2. You may want to hit him up for thoughts. I can't find his username off the bat, but again the forum over there is free, so you could fish for information free.
The Catalina 25 is a great starter "large" trailer sailor. It's not really to be trailer launched each time (it can be done, its just a LOT of work)... it IS great for a boat slip, and is a decent sailing boat. It's very forgiving, and parts are still readily available for these.
You can also call on the knowledge of the association to help you find a boat that is at a decent cost, with less work. There are even some for sale by members that have been lovingly cared for.