Thank you for the reply.
So if we were to omit Austin,Texas, would this trip be more manageable? A friend suggested flying out from Buffalo to California, renting a car from there, and then driving east towards Nevada, and returning the vehicle in Buffalo, and driving back to Toronto in our own vehicle, which we left in Buffalo.
That way we can enjoy the road trip part (as we will be driving back) and at the same time saving time and enery during the trip.