My pick would have to be the A Whole Nother Story trilogy, in which (spoiler warning) you can only travel back in time. But because time is in a loop of sorts, if you go before the beginning of time, you will be at the end of time. From there you can go back to any time you want to. And time paradoxes cannot be produced. Plus, your memories from the previous timeline exist as well as the memories from the new one.
I just started it and it just feels very aged. This is my first chrichton book and it doesn’t feel as if it’s written by a renowned writer.
If it helps, I love Crichton but Timeline is by far my least favorite book of his. I had such a difficult time getting through it. Other Crichton books I’d not read again are Next, State of Fear, and Rising Sun.