If you drive 200miles in one day once a month a snapped cambelt would cost £££ in recovery, onward journey and maybe over night stay.
If you drive a 200000 mile old car without breakdown cover, you’re braver than me.
How’s the rest of the car? The list of faults is enough to put me off investing in it, but if the rest of the car is solid and trustworthy you’ll need to spend a chunk to get anything better.
(White smoke doesn’t necessarily mean water btw, it’s commonly repeated but my mondingo smokes white/very light grey on an injector failure. And let’s be honest, smoke on a 200K diesel isn’t anything out of the ordinary. It could be a useful symptom but you can’t rely on it imo)
None of the work should be that involved, assuming it’s not all corroded together, which it probably is. Even little jobs start to become a bastard on older modern cars with tight access and small fasteners etc. So frinstance, brake hoses are often fitted to the shell before other bits go in, making access a bastard with “remove part X” And then part X turns out to be held on with 6 machine screws that have corroded away to stumps, so it’s easier to break your arm in the middle and cut off your pinky and shove it through a gap the size of your eye than it is to actually move the whateveritis.
From the sounds of it, I’d run it into the ground. But ymm literally may vary.