Originally Posted by bookfanmd
You could try Janet Evanovich's Stephanie Plum series. There are some "between the numbers" books but they are all self-contained and don't affect the main series.
Actually, wasn't one of her sub-stories resolved in one of her "between the numbers" books? In one "numbered" book her sister was engaged, then she and the lawyer decided not to get married in a "between" book. Right?