The best place to always start your research is your own Public Library.
Even if Local History Books aren't available for the area, most libraries will be able to order them in through Inter- Library Loan.
For this it is best to give as much information on the book as possible, such as Title, Author, ISBN # if known.
Most libraries can also order MICROFILMS, MICROFICHE and other items from the National Library of Canada who participates in Inter Library Loan throughout the world.
HOWEVER make sure that the ordering library has a microfilm/microfiche reader as the microfilm won't be allowed to leave the borrowing library.
Another good place to start is at the Ontario Archives who also participates in ILL. A quick search of the web site will enable you to find the microfilm numbers you need to order film. If you follow the instructions carefully you shouldn't have any problems.
Another Institution that participates in ILL is the National Archives of Canada.
Again if you follow instructions carefully, write down all the information you need to take to your library for ordering purposes you shouldn't have a problem.
All of the above sources have information on the Parry Sound District, and the Muskoka Districts in Ontario, Canada.
Another great source would be your local LDS Family History Centre. Locations for these centres are available on their web site.
Also don't count out your local Genealogical Society even if it isn't anywhere near the area where you are researching. For example: The York County Genealogical Society which has its holdings at the Richmond Hill Public Library contains information for most counties in Ontario and all over the world.
Then one should never forget the importance of Census, Newspapers, Cemeteries and School records.
When sending letters of inquiry ALWAYS include a SASE. It may not guarantee you a reply but it will increase the chances.
Last of all remember that there are so many people researching their family lines right now, it may take up to 6 months in some cases to receive a reply.