Hi Margaret,
It also appears to have been a school ...
Ref:
http://www.downmemorylane.me.uk/Antrim%20W1.htm [Photo 2746]
"This is Wilderness Lodge which used to be at the corner of Oriel road and the Ballymena road opposite St. Comgalls ..."
A search for "andrew spearing" in the British Library's 19thC Newspapers Collection throws up 74 finds, ranging in date from ...
... serving on the Grand Jury of Cork City;
[The Morning Post (London, England) October 31, 1832]
... going bankrupt as physician-surgeon at Westfield, Liverpool-Road, Patricroft, Lancashire.
[Liverpool Mercury May 2, 1900]
... and, of course, many entries for Antrim (town) where yer man worked in the Medical Hall.
A short description of the funeral of your "esteemed gentleman" ancestor mentions:
Removal from his late residence, Riverside, Antrim, for internment in the New Cemetery.
Wreath from Lords Massereene-Ferrard.
Masonic Lodge No. 28 and L.O.L. Orange Lodge No.13 in attendance.
The chief mourners were Dr. Andrew Spearing, nephew; Messrs. G. M. Malone, Belfast, son-in-law; and Henry Malone, grandson.
[Belfast News-Letter December 21, 1899]
----
A search for "wilderness lodge" in the British Library's 19thC Newspapers Collection throws up 44 finds, but none are in the Irish newspapers.
PRONI's e-cat draws a blank on the exact phrase, but does list documents (e.g. D203, quoting the OS Memoirs of the 1830s) which describe a 37-acre designed "French" garden named "The Wilderness", lying beside the river in Antrim parish but adjoining The Grange of Muckamore.
Capt. Jock