I would go for the larger fridge as well, whether to have them install the over-priced solar and battery setup is your choice. Might be wise to have it done aftermarket using better components, a pair of 6 volt golfcart batteries, and more than likely end up with additional wattage for what they are charging.
Most factory installed systems tend to utilize less than ideal equipment and wiring. For best results when RVing off the power grid is to have a quiet inverter genny along with a fast charging smart converter for times when solar can't keep up. Congrats on your new rig, welcome to the RV lifestyle.
