Owning a Class B I have just a couple of comments. First make certain the RV you rent have forward facing seats other than the two front seats. For example, like many RV's mine model comes with a sofa with lap belts on the side behind the driver. Many Class B's have a sofa in the rear with lap belts, but be aware that your two year old will be riding over 10 feet behind you. There is at least one model I know of with 4 front facing individual seats but they are not common.
I doubt the OP will return. This thread is 5 years old and the OP hadn't returned since.
On edit: I read the whole thread (good on me) but never noticed the date! There is a similar thread on another forum that is current.
Dave