Well I haven't done much of my acoustic stuff with Sonar yet and this may or may not be useful to you but I found R-Mix was absolutely great for cleaning up room and other noise. Made it easier to do the rest of my tweaks because I was working with a nice clean signal. Trying to get rid of that stuff with traditional methods is daunting for a semi-beginner mix engineer such as myself.
As far as mix/recording techniques there are lots of good ideas to be found over on Groove3 if you can afford to drop 15 bucks or whatever it is for a month pass. There is one vid mostly about micing/recording that has a pretty good section on micing a solo acoustic singer/songwriter. IIRC too there is a pretty good Cake Blog post on micing acoustic guitars as well but I forget who wrote it or if it actually was the blog. I think there were a bunch of vids attached to it to show the various techniques and how they sounded. Very in depth.