I would say 42 TPUs=90-110K RCI points, although it is not a exact cross-over, plus these caveats:
usually a 2Br only cost a few more TPUs than a 1BR, whereas it is usually significantly more in RCi points.
peak weeks seem to get/cost more in TPUs, whereas in RCI points it seems to be more by season, so sometimes you can get a better deal in RCI points for peak weeks.
For getting a prime week, I like points better, and have gotten some units with points that never even showed up in weeks (even though the resort had weeks as well). Ex. S. Cal. in July, Bermuda in Aug., Easter at DVC. I would not have gotten any of those with weeks (I checked for a few weeks after to see if there were any weeks deposits--nope).