ICC/ANSI A117.1 is your best guide. Single family (R3) are not required to be accessible unless you have 4 or more units - i.e. quadplexes (is that even a word?). Thus, a single family detached house has no requirements. I believe that you can pick and choose which parts of the house you wish to make accessible.

ANSI 117.1 has all clearances and ADA guidelines for all building components. Most of these diagrams and descriptions are also available at this website:

http://www.access-board.gov/adaag/html/adaag.htm

I should clarify a bit more. This is a residential situation where we have been asked to design an accessible guest suite that could be used for the owner’s parents and down the road could become the master suite if navigating the stairs becomes difficult.

I’m not looking for a minimum standard, I’m looking for a “best practice.” For instance I have read that the 5’ turning radius is just not a comfortable tolerance to live with day to day and that 6’ is much better for navigating your home daily to avoid frustration.

There are a number of books at Amazon resulting from a search on “accessible design” but I fear they are geared toward home owners and not architects and won’t be concise enough about what I want to learn. Can someone make a recommendation from experience?

- Thanks

for single residential home, the requirement should be set by the owner. a wheel chair bound user will need a different design from a blind user. if the guest suite has a kitchen, or any kind of built in furnishing, there are requirement spelt out by ADAAG and ANSI 117.1. Depending on which jurisdiction you are building your project, you should also check with the building code.
It is all based on your design logic. If you are not sure, you should get someone to review the design and the scope.
Now... this is going to sound like I am selling myself... but I will be glad to review your design. I had quite a bit of accessibility design background for hospitality work. We can talk offline.