First it's ALWAYS worth spending a Saturday checking out boats...
Online hunting is a good start, but be aware that there's no way to know when those pics were taken, so even that's just a starting point.
Local CL listings seem to be more the norm for small to midsized boats, with the advantage that they are usually not too far away to look at.
Look for something clean, no immediate nasty 'smell' when you step below (but most older boats have some residual odor - mold and rot smells are indicators of problems. Fuel smells can usually be tracked down but could indicate a weeping tank.. not good.
Clean bilges and cubbies are indicative of good care - a clean engine area the same.
Generally I think you'll get a 'good' feeling when it's close to being right.