Teen fiction book about boy growing up in the 1890's Midwest

I'm looking a book I read in the early or mid 1980's. It's part of a series of books I believe. The main character is a boy growing up in turn of the 20th century Midwest (perhaps Kansas). In one story the boy describes how when one of his siblings gets sick his parents try to get the other siblings sick as well so they can all get the immunity. The main character wants to get sick first so he can get his siblings sick. This leads to humorous consequences. The main character is kind of a Huck Finn characters, always on some adventure with his friends.

Hmm.

The bit about deliberately exposing siblings so they'll all get sick at once, and the sneaking around trying to get sick first, sounds like something from one of the Great Brain books, and the time period is right, but they're set in Utah, not the Midwest, and they're aimed at elementary school kids, not teenagers, so I don't think that's right. I'm mostly mentioning it here because otherwise someone else will, and I wanted to say why I don't think it's right.

Hi lorax,

The details I mentioned are all from 25+ year memories. So I could be a bit off. I'm fairly certain about the time frame and the plot details. Not so much on the setting and book being for teens. It could have been for pre-teens.

Well I'm working from memories of comparable age, but in that case you may want to check the Great Brain books.

The other details I remember, though they may be from other books in the series, are the main character's father getting indoor plumbing (the first in the town), and characters being lost in a cave. Any of that sound familiar?

Sounds like the Great Brain to me. Love those books!

So I did bit of research on the Great Brain nooks. The "water closet" plot sounds familiar as well. This could very well be the books I am looking for. :-)