There were several field hospitals or aid stations of the Second Corps, including:
-West bank of Rock Creek on the Bushman and Schwartz farms.
-East bank of Rock Creek.
-Jacob Swisher farm east of the Taneytown road.
-Granite Schoolhouse.
-Jacob Hummelbaugh farm.
-Sarah Patterson farm.
-Nathaniel Lightner farm.
-Catherine Guinn farm.
-Peter Frey farm.
-Section of Camp Letterman General Hospital.
Or, in other words, most of the farms or dwellings behind the Second Corps lines on or east of the Taneytown road extending to (and even beyond) Rock Creek, with the notable exception of the George Spangler farm (under the Eleventh Corps).
As for Confederates taken to Second Corps hospitals, they would include any regiment that fought opposite the Second Corps (excepting First Division in the Wheatfield), namely Pickett's division, Heth/Pettigrew's division, the brigades of Wright and Lang in R. H. Anderson's division, the brigades of Lane and Scales in Pender/Trimble's division, plus a few others from assorted commands, including 13 MS (and Barksdale himself), Avery's 21 NC, and Thomas' 45 GA.
If you have someone or some regiment in particular in mind, we might be able to confirm their presence in a Second Corps hospital.