Some of your text contrasts are a little low to be useful for low vision. In general, any text:background contrast that's less than 4.5:1 is going to create problems for low vision users. Grab yourself a copy of the free Color Contrast Analyzer tool: http://www.paciellogroup.com/resources/contrast-analyser.html to help with checking contrasts across the site.
The colour scheme you have chosen is going to cause problems with colour blind visitors who have Tritanopia (a fairly rare form of colour blindness) as it's not possible to distinguish the links from the plain text. You could deal with this by ensuring that all links outside of the nav menus are underlined with the
text-decoration:none; set on the hover, active and focus states. This means that people won't have to "scrub" the page to find links if they can't distinguish the link colour.
You don't seem to have taken sighted keyboard navigators into account. Suggestion: try navigating through the site using only the Tab key and you'll see what I mean. To address this, apply a background colour to the a:active and a:focus states. What I often do is reverse the default link colours, so in your case, you'd have white text on a brown background. Then try tabbing around the site again and you'll see the immediate difference that such a small change can make.
Another neat CSS trick is to apply a different, contrasting border to the :focus state for all inputs and textareas. If you also style all submit buttons (using say
input[type="submit]), you can also change the colour for the hover and focus states here too.
All told though. it's really nice to see someone taking the time out to address the needs of all potential visitors and it goes a long way to prove that accessible sites can still be visually appealing. Well done you! :-)