The Lou Jones she refers tomust be Louis Einon Jones who was a witness at her 1916 wedding, probably the Best Man.
As she refers to 'little Loyd' [born mid 1928] & says the 'children have such fun' I would put Dorothy at under 14 and Billy as over 2, thus my assumption for the year the letter was written as 1930-1931.
Map showing Roselawn Avenue where Topp lived early 30s. Later, 1939, living with her daughter in Erskine Avenue.Then at 3431 Yonge Street from 1941-1955\; this ~3 km north of junction of Erskine Avenue with Yonge Street