Me thinks the OP may have been saved by a dead or near dead battery that stopped you from getting the full 24v's.
The advice on new batteries and tires is sound, I would go there.
You may want to offer up how you plan to use this rig, ie: boondocking, occasional dry overnights, or always on shore power. This will get you good advice on this site as to the array of batteries that will suit you best, as in 2-6's, 2-12's or even just one 12.
Anyway congrats on the new camper and enjoy it. Family camping with small kids is so great. Memories that will last a lifetime. Even when the 8 year old plays with buttons.