Celeste Holm played Abigail Townsend in the sitcom 'Nancy', about the President's daughter falling in love and marrying a small-town veterinarian in Iowa. Ms. Townsend served as sort of a chief of staff for Nancy Smith and her ideas of what was best for the girl often clashed with Nancy's desires.
It's pozz'ble, just pozz'ble (as Mushrat would say), that Abigail Townsend could be related to rich private investigator Charlie Townsend - if he has a counterpart in the parallel world in which we'd find 'Nancy'. See, that show can't be in Earth Prime-Time because there was no President Smith in Toobworld. Toobworld has to follow the real world with the line of succession.
'Nancy' can't be placed in the 'West Wing' dimension either. Their POTUS collection diverges from ours probably right after Nixon (the last real President to be mentioned) although Ford, Carter, and Reagan might still have served. After that, they had Presidents D. Wire Newman, Owen Lassiter, and Jed Bartlet (with Glenallen Walker serving for a few days under the 25th Amendment.)
However, President Smith could easily fit into the same TV dimension in which we'd find the sitcoms 'Hail To The Chief', with President Julia Mansfield (played by Patty Duke), and 'Mr. President', with George C. Scott as President Samuel Arthur Tresch. Apparently that world wouldn't have had any of the same Presidents as the real world in the late 20th Century. And because 'Nancy' is also a sitcom, I think it would make for a good fit.
Two other shows might also fit into this TV dimension: 'Spin City', with its alternateevee Mayor of New York City, and 'Yes, Prime Minister' with a different leader of the British government than to be found in the real world. And its prequel of 'Yes, Minister' would also be included.