what kind of town is bricksville in chapter 21?

From the text, we can infer that the town is poor and rundown. Prosperity is at low, and many people have moved away. In general, there are a lot of people hanging around.

The stores and houses was most all old, shackly, dried up frame concerns that hadn't ever been painted; they was set up three or four foot above ground on stilts, so as to be out of reach of the water when the river was over-flowed. The houses had little gardens around them, but they didn't seem to raise hardly anything in them but jimpson-weeds, and sunflowers, and ash piles, and old curled-up boots and shoes, and pieces of bottles, and rags, and played-out tinware. The fences was made of different kinds of boards, nailed on at different times; and they leaned every which way, and had gates that didn't generly have but one hinge--a leather one.

All the stores was along one street. They had white domestic awnings in front, and the country people hitched their horses to the awning-posts. There was empty drygoods boxes under the awnings, and loafers roosting on them all day long, whittling them with their Barlow knives; and chawing tobacco, and gaping and yawning and stretching--a mighty ornery lot. They generly had on yellow straw hats most as wide as an umbrella, but didn't wear no coats nor waistcoats, they called one another Bill, and Buck, and Hank, and Joe, and Andy, and talked lazy and drawly, and used considerable many cuss words. There was as many as one loafer leaning up against every awning-post, and he most always had his hands in his britches-pockets, except when he fetched them out to lend a chaw of tobacco or scratch.

All the streets and lanes was just mud; they warn't nothing else BUT mud --mud as black as tar and nigh about a foot deep in some places, and two or three inches deep in ALL the places. The hogs loafed and grunted around everywheres.