Twain thinks of nobility as little better than animals themselves, as they sleep well on the ground with the critters and "as for a bath, probably neither she nor any other noble in the land had ever had one, and so she was not missing it." He calls them, by modern standards, "merely modified savages."
They don't take food with them, either, and are thus accustomed to starving ("fasting") on long journeys. They'd prepare by pigging out before the trip.
The nobility, he observes, are also snotty and condescending to the lower-born. When they come upon some "freemen" working a road, he offers to dine with them and "My lady put up her scornful lip and withdrew to one side; she said in their hearing that she would as soon think of eating with the other cattle." Although they are presumably free, they are so beneath her that she thinks of them as mere cattle. In his opinion, the "freemen" were all that was worthy of respect in the whole kingdom; in comparison he refers to the nobility and king as "dregs" and "refuse" (trash), as they were "idle, unproductive, acquainted mainly with the arts of wasting and destroying, and of no sort of use or value" and lived off the largess produced by the unfree "freemen."
This is, of course, Twain's commentary on how the rich and privileged of his own time worked and deserved less than the proletariat, who worked and were taxed for the benefit of the wealthy.
Some things never change.