Many years ago, I saw a comment on The Archdruid Report from a teacher at an upscale private school. They’d done a class exercise where students had to answer which time period they’d want to go to if possible and why. The most popular answer was that they wanted to live in the 1960s. The teacher then pointed out they didn’t have to go to the past, they could also choose to go to the future. None of the students wanted that. These were upper-middle class students in the United States, and even they didn’t believe they had a future better than the 1960s to look forward to.
The past has an advantage: we know far more about what it was like than how the future will be. If you want to reduce your risks, it’s better to choose to go to a historical period rather than the future.However, if I had the choice of choosing an era to move to, I’d choose a hundred thousand years in the future. That’d be dangerous—maybe Earth can’t sustain human life in a hundred thousand years, or maybe the human societies which exist will be terrible.
But it could have a huge upside—maybe life for humans is way better in a hundred thousand years than it is today. Maybe the humans of that time (or a nonhuman species) will revere me as a precious example of a historical human. It also might give me a chance to learn what the historical trajectory of the society I grew up it will be.
Why a hundred thousand years and not a million years? Or a billion years? At some point, it become inevitable that the Earth won’t be able to sustain human life, so I’d want to avoid that period. A million years from now the Earth may still be human-friendly, but might be so transformed I wouldn’t recognize anything. A hundred thousand years ago seems deep enough in the future that I could witness some dramatic changes while still having a decent chance of integrating into whatever societies—human or not—exist.I get what the schoolteacher was saying, we’re currently in a society where even the rich believe that major society-bashing catastrophes lurk in our future. The optimism I recall from as recently as the 1990s is gone. Yet, however pessimistic I am about the next century, I still hope for a bright deep future.
If I were given such a fantastical opportunity, might as well make a big bet rather than play it safe and go back to the 1960s.
The Notes Which Do Not Fit 
I find interesting that the children of the upper class do not fear to be involved in the Vietnam war… either they don’t know history or they know better, i.e. that it would have been others to be send to (the) massacre
Assuming they would’ve also been upper class in the 1960s, yes, they would’ve had ways to avoid that. (That’s in the United States, the upper class in Vietnam couldn’t avoid the war).
I think your 100,000-year idea is a good one. It seems likely to me that, in that time frame, humanity will either figure out how to survive without fouling our own nest to the point of it being uninhabitable, or perish. If humanity perishes, what life survives will re-establish itself fairly quickly. In other words, homeostasis will flick us off and re-stabilize.
A new homeostasis may not be human-friendly. I’d prefer to find human or post-human societies which have figured out how to survive in ecological balance.