A cross bike or a hybrid would work for unpaved paths not bouldery rough areas. Some cross bikes can take wider tires than others so you may want to look into a wider tire if you want the bike to be more stable. Weight on a bike is relative. The more you spend, the less weight they usually have. Some very expensive 29ers might be lighter than a cross bike or hybrid just because they are made of a lighter material and speced with more expensive lighter weight parts. My steel Redline cross bike is heavier than my Klein hard tail mountain bike for instance. Another thing you may want to consider is that if you are riding off road, you may want good clearance from your top tube, so that may be an issue for you with a regular triangle bike; I just don't know what you are looking at.

Also, I don't know how tall you are, but 29ers used off road may not be the best best for a short woman or man.

spoke