Ok, I noticed a lot of views but no replies, so I figure that there are others looking for the same answer or something like that. That's why I decided to share what I learned in my most recent attempt at this Lifetime Wish.
In hindsight, it seems pretty simple, and I don't know why I didn't realize it in previous attempts. Anyway, here's what I did in a nutshell for those that are interested. The first step of course is to make a trip to the normal future. I don't know if it's necessary, but it's what worked for me. Do whatever you want while you're there, like steal everything that isn't bolted down
. I think I netted around 18k just selling the oculo computers, windcarvers, jetpacks, and holo discs, kept about one of each for my Sim. Not that any of that matters to the LTW, I goofed around with opportunities and visited my descendants for a couple of days then went back to the present.
There certainly isn't any order that you have to do it, but I triggered the Dystopian future first and did the opportunities needed to make the change. Naturally, after that, it was time to return to the future and see what had changed. My Sim tried to help Emit with his research, but he kept getting the ones he had already done, so he payed a visit to his smelly descendants instead and improved his relationship with them in spite of the smell. On the way back to the Community Center, he dug through some garbage piles and explored a couple of rifts. I doubt this mattered for the Wish, but I figured he should fully experience this future. There were a few other things that he did during his stay like bot building and such, but those don't really affect the Wish.
It was time for a quick trip back to the present to undo what he had done to the future, and this was the step that I skipped in previous attempts. I think it might be why I couldn't get the Wish to complete before. My Sim did what he had to do to restore the future back to the normal future he had visited before, and then it was time for a quick trip back to it to make sure things were the way they should be. This was a short trip with the usual visits to the future offspring and a little more bot building before heading back to the present once again.
It was time now to trigger another change to Utopia now. He jumped through all the hoops and turned the residents of Sunset Valley technicolor for a while. A visit to the military base for widespread dispersal of the dew and Emit, or a hologram of him, showed up to inform my Sim that a statue had been erected in his honor as Time Keeper. The Wish still hadn't completed, so it was time for another jaunt to the future. I expected that I would have to restore it to normal again for the Wish to complete, but luckily that wasn't the case. As soon as my Sim arrived in the Future, there was joyous music, and my Sim's lifetime wish was complete.
Well, that turned out to be more long-winded than I had intended, but the storyteller in me got involved. I don't think it matters what order you use, but it seems that restoring between Dystopia and Utopia is essential. It also doesn't seem to matter what if anything you do in the future, but you might as well enjoy your time in each while you're there. Hopefully, this will help anyone who's having issues with it and help with any guide that might be written about the Wish. Now, I'm off to see if I can get all 5 Legacy statues with that same Sim before he croaks.