As Igazor asked, I am starting a new thread to ask about my problem with traveling to Oasis Landing.

I'm at patch 1.69, and for purposes of testing I was using only the following mods:
Traveler 87c
Overwatch 122
Errortrap 100

I'll list my testing steps after this, but in short I found it impossible to travel to Oasis Landing through the time portal, no matter whether I saved at the prompt or not, or whether I took one or two sims. Also, Oasis Landing wasn't listed in the Travel menu when it was accessed through either the smart phone or the computer.

First test:

Started a household in Sunset Valley.
Fixed the Time Portal and then saved the game.
Tried to enter the Time Portal with one sim.
Chose not to save when prompted.
Result: The game only loaded for a short moment, and then returned to live mode without having traveled.

Second test:

Loaded aforementioned save game.
Tried to enter the Time Portal with two sims.
Chose not to save when prompted.
Result: Same result.

Third test:

Loaded save game.
Tried to enter the Time Portal with one sim.
Chose to save when prompted (save game is discarded after test).
Result: Same result.

Fourth test:

Loaded first save game.
Tried to enter the Time Portal with two sims.
Chose to save when prompted (save game is discarded after test).
Result: Same result.

Fifth test:

Loaded first save game.
Tried to travel to future via Travel menu.
Result: Oasis Landing is not one of the options.

I forgot to mention, traveling to vacation worlds via the Travel menu seems to function without any problems.

Until a coder sees this and answers, I have two more tests for you to try (if you can) based on this new information.

1 - Has this game ever seen the future before and is there an Oasis Landing nhd file in your save? If so, perhaps it has become corrupt. What happens if you pull the nhd file out to the Desktop for safekeeping and try again? I know this will disrupt any progress your game has made in the future, if there had been any, but it's just a test and the old nhd can be put back again after a quit without saving.

2 - Do things happen any differently with Traveler v86 in place, and the scriptCache.package file cleared?

1. The game has never seen the future before, and there is no Oasis Landing file in the save.
2. When using Traveler v86, I can travel to the future without problems.

As a bonus, I went saved after I went to the future and back under Traveler v86, and reloaded the save under v87c to try again. Mostly to see whether the existence of the nhd had any effect.
Result: It didn't. I still couldn't travel to the future with Traveler v87c.

I just tested Traveler v87b, and I was able to travel to the future without problems.
Oasis landing still did not show in the Travel menu, but I do not consider that a problem.

The problems thus seems to have been introduced with v87c.