If you can get a picture of the flyback a little zoomed out so I can see the whole thing I could say for more sure, but it looks like that wax is not all that bad.
That blooming or whatever is a concern though. It could be the connection I mentioned, and that is easily checkable by just trying to lift up the corner of that board. If it moves it needs to be resoldered. Otherwise, these things used to have a picture get bigger and bigger with higher brightness when the 3A3 high voltage rectifier got weak. There is actually a solid state replacement for those tubes. Finding one is another story. Also, if you use the solid state replacement, when you shut it off do not turn it back on for at least a minute or two.
Replacing the TV with a newer model is nice, but destroys all intrinsic value of the piece of course. Like a Chevy with a Ford engine in it. (why anyone ever did that is beyond me) A company I used to work for did it all the time. People had these old tube sets and there was a guy who came in and put a new TV in. When possible we connected the stereo amp to the TV for better sound, most of them were stereo by then.
I doubt your unit does that but I could be wrong. The one we had which was close had a speaker switch on the power button of the TV and used the stock TV chassis audio circuit. I am pretty sure yours is a bit newer, so I really don't know.
But really, how is the stereo ? Give that the full inspection. You said it sounds good I think, is the FM working well ? And the TT, well those things can be weird. Some had a self weighted cart in them, which actually played quite well. The one we had, the cart was replacable with an Astatic 353D, which was one of the best sounding ceramic carts I ever heard. that was the era when ceramic carts were getting better, lower tracking force, higher compliance and better frequency response. All the major players were doing it, Zenith and Magnavox for example. And Packard Bell made a couple that were really kickass which may have had magnetic carts in them.
As late as maybe 2006, people paid good money to have old consoles fixed. I walked into work (good money job) and they give me a console stereo to work on. At first, I was like "Are you kidding me ?". Then I found out they had cleared a $350 estimate. Well I tried to give them their money's worth. And some of these things take alot of work. The customers seemed happy.
I really kinda wonder what happened. When I was young, we kids would lay on the floor watching TV. It was great. Floor model. We had three channels and had to discuss what to watch, now there are three hundred channels and nothing is on. Orwell said less is more, but it seems that now, more is less.
But I an going to say one thing about that CTC25 TV you got there. Once you get the tint control unsiezed and adjusted correctly, if you watch an episode of Star Trek from back then, Spock is green and everyone else isn't. That is because the color decoder was accurate and did not have "flesh correction".