Frost Avenue is seedling 3610 according to AHS records.
3610 = 3011 X T2622. 3011 would have been tet, but I found no record of its conversion. The (undocumented) conversion could have happened a generation earlier, as this line originates in diploids.
3011 = "Pink" X 2214
2214 = Unk X My Belle
If 2214 was converted, then the pink mate would have been tet. Otherwise, if 3011 was converted, the "pink" mate was dip. I think "pink" in the notebook means "I don't remember other than I took 2214 to several pinks in the garden."
2622 = 2020 X WH1 (a seedling Oscie selected from the last seed crop of his friend, Jim McKinney, who died in 1979.)
2020 = 1611 X Little Infant
1611 = "S.V." (Spalding violet seedling) X either Iron Gate Glacier OR Iron Gate Ice Berg. Oscie's key for IGIB said it could also mean Iron Gate Glacier.
Oscie referred to Frost Avenue as "a dream-maker in the garden."