@ ittech,
I do not know if you and your wife can do medicals separately. If you read the medical instructions pdf file they sent you, you will find this.
"The medical examination must be performed by one of the physicians listed on the CIC "List of Designated Medical Practitioners " (i.e. doctors). If possible, all family members should be examined by the same doctor. To find the Designated Medical Practitioner located closest to your home, consult the internet site: http://www.cic.gc.ca/dmp-md/medical.aspx "
I think you have 60 days to do the medicals, or the application processing will be delayed.
About the rest,
you have to print out all the forms they sent by E-mail before going to the medical examiner. They wont send anything by post. I suggest you read all the files they sent you.
Here is the listed doctors near Boston MA.
http://www.cic.gc.ca/dmp-md/medicalinfo.aspx?CountryID=2040&ProvID=19007&ProvinceName=Massachusetts&CountryName=United%20States%20of%20America
things to bring:
All fees related to this medical examination are your responsibility.
2. Please bring the following to your medical appointment:
two recent colour passport size photographs of each family member
eye glasses (if applicable), list of prescription drugs taken or any relevant medical report(s)
original passport(s) or other proof of identity
Hope it helps!