So, just as the title suggests, I picked up this 453 without any prior knowledge of these vehicles.

https://photos.app.goo.gl/sjawu88i2o52b2DC9

I'm looking for some tips as to what I should be looking at/addressing first. I can see that there may be issues with the transmission:

https://photos.app.goo.gl/YZBggpwWvx36Huxf9

But it also came with this:

https://photos.app.goo.gl/a1X3Y4YZ8jyhDEXu9

The bottom of the tub looks to have a fairly fresh coat of paint on it. The inside too, although it looks like it was exposed for a while and has started to rust again:

https://photos.app.goo.gl/TM8DB2HvfuoEeMLq7

To start cleaning it up, should any of this get cut out and welded back in after?

https://photos.app.goo.gl/19dP4WjzN4JytbU56

I'm just looking for some direction here, on the best plan of action, so that I can do things in order and not have to go back and do it twice!

Thanks!