Nothing wrong with replacing the engine and transmission.
I am still running a rig from the "old days" a 87 suburban 3/4 ton 4 x 4. It has served me well for hunting and offroad use for decades.
This is the first year they put in fuel injection. Second to last year they ran a straight front axle. Has the dinosaur turbo 400. Installed a dyneer nospin aka detroit locker. It has 460,000 plus miles on it. It won the FIX IT or dump it decision.
In the SW no rust to worry about. On its third engine a roller lifter 350. Turbo 400 just had its third rebuild. As parts wear out they get replaced. It is reliable and never have to worry about the paint getting scratched up. Or body panels getting roughed up.
To date it has "bumped" into two lighter vehicles and they lost. The tires tend to fend off stuff. Scrubbed body panels on other car or even driving over the front of one! Its looks keep many people from trying to take advantage of me on the road. Never worry about it in parking lots. When the paint starts looking bad I rough it up and shoot it with around 11 cans of Rustoleum 2X paint.
Jealous as heck.
You are living my car dream.
I buy older cars, higher miles.
Change oil....occasionally,
DGAF about oil changes, the body will fall off before the engine dies.
One Subaru wagon took 3 cans of spray foam to close the holes in the
rockers. Had to use duct tape to keep it from falling out until it set.
Finally parked that car for fear of what might happen to passengers if
I had a big wreck. Like hitting a squirrel!😂😂😂😂
Be awesome to maintain a car knowing it's life span was up to me.