How good the solar works for you will be dependent on your style of camping. If you like camping in the trees then the solar panel won't be of much use. A small genny will be money better spent. If you like being out in the open then the solar will give quiet help to keep the batterys up depending on what you have on & amount of sun. Solar is not going to equal what you charger can do with the genny.
Also, when it is time to replace those group 27s look into getting group 31s, same or close case size, or a single 4D.