I think a lot of people with V6 3rd and 4th gen Explorers have your experience but a lot do not. Getting yours with such low miles is a big help in keeping a vehicle reliable. Your transmission replacement probably made more sense at 70k miles. If it happened at 150k miles and more age on it would you have made the same choice as easily? I see so many people come to these forums having bought a higher mileage SOCH V6 and are devastated because they have engine/transmission problems not long after purchasing them. Then end up being told they have a timing chain/guide repair or a transmission replacement that costs about what they paid for the vehicle. Then their dilemma becomes whether to do one of these repairs when the second could be just around the corner. These people might have spent all they had on this vehicle and now it is an albatross around their neck. This is why I can't recommend vehicles with a SOHC V6. It is a BIG roll of the dice to own one. Even you had a transmission replacement well before it should have been necessary which goes a long way in making my point.
This risk is greatly mitigated if one can do all, or a good amount of, the wrenching themselves. However, the vast majority of people can't do this and this makes repairs requiring engine removal and/or installing/purchasing a remanufactured transmission much, much more expensive. Especially when factoring in all the other repairs a typical 3rd/4th gen Explorer/Mountaineer sees as the miles rack up. I consider it a minor miracle that you never had to replace at least one wheel bearing in 186k miles. Also, consider your five weekends of labor at say 16 hours a weekend would be 80 hours. At a reputable shop this would be $80-$100 per hour and added $5k-$6k in repair cosst to your numbers.
Yeah, not a single wheel bearing... also, I think I went through like 3 sets of tires. The brake calipers were still original also.
But I routinely did the maintenance. I flushed the brake lines (completely) twice during the life of the car, replaced the fuel filter twice, crank PCV valve, umm.... original oxygen sensors. I did replace the catalytic converter with a Magnafow "Direct-Fit" high-flow catalytic converter with mandrel-bent tubing.... but I did that around 50k miles, and not because the old one needed replacing, but because I wanted a bit more horsepower and efficiency on the highway. I never ended up changing the differential fluid, though I'd wanted to several times, but never got around to it. I never changed the transmission filter, though I sucked out and flushed the fluid twice during the time I owned it. I also flushed the cooling system twice. I used everything from Castrol GTX to Royal Purple... all synthetic. And I think I went through ~3 or 4 batteries.
I was not easy on the car either... I mean I really beat the piss out of that car. I was a lead foot, and would floor it quite regularly to pass (never any burn-outs or anything)... but every toll plaza was like the Grand Prix of Miami.
Never had any timing chain rattle. My neighbor also had a 2-door Explorer (though an older one than mine.. pre-2001, and he finally had a head gasket blow at 230k miles. It was before I ever got my car.
Big take-away for me though is that people should never expect to buy a really old beat up car, and not have issues with it. I don't think this is particularly unique to the Ford Explorer so much as it is a used car in general with high mileage. When I buy a "new" car... I always shop for something that has 35k or fewer miles, and is no more than 7 years old.
We've all been at a point in our lives where we don't have a lot of money, are just starting out, etc. When I was in my early 20s, I'd have to go to the used tire shop to get cars. I empathize with what you're saying... and it's unfortunate that people would buy something old, worn, and unknown, expecting to get long life out of it. If you take care of a car, you'll get a lot of years out of it. But if you get something really beat up... expect to spend some time and money.
EDIT: Total tangent here... but I just started (and drove around the block a few times) my 2002 Ford Crown Victoria LX. Last time I started it was about 8 months ago I believe... possibly longer. It was well before COVID was a thing. I tried to start it earlier in the year, but the battery was dead, so I charged it a few months ago, and just not got around to starting it. It was less than 1/10th of tank of gas (maybe some had evaporated) and it started right up. I filled the tank with a Jimmy can that I just bought today... car started right up... I was so impressed. I was thinking of selling the Crown Vic (it's all original, has 50k miles on it), but after driving it around, it had so much power and runs so smooth and quiet, I pretty much changed my mind... ugh.
This is what I drive now, 2009 Ford Explorer Sport (picture from early 2020):
And this is my 2002 Crown Victoria LX (older picture taken in 2014, I've since moved, but it's exactly the same... just been garaged):