Queen entering museum, hospital, or gallery (8)
I believe the answer is:
verandah
'gallery' is the definition.
('verandah' can be a synonym of 'gallery')
'queen entering museum hospital' is the wordplay.
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'entering' indicates putting letters inside.
'museum' becomes 'vanda'.
'hospital' becomes 'h'.
'er' inserted into 'vanda' is 'veranda'.
'veranda'+'h'='VERANDAH'
'or' is the link.
(Other definitions for verandah that I've seen before include "16 21 [INDIAN IMPORT]" , "Portico" , "Roofed area on the side of a house" , "Porch" , "Roofed platform adjoining a house" .)