Measure resistance of multiple unknown resistors with single analog pin
I would rather use switched current sources instead of using BJT's to switch voltage. With the current source, you can also change the range so you can also measure smaller resistors more precisely than with this setup. With a current source, you wouldn't need a second resistor to build a voltage divider, but can instead directly measure the resistor. If you use a single current source an an analog multiplexer, you can use a known resistor for calibration of the setup and your voltage reference. The current source will also eliminate some of the inaccuracy that you get as the 5V supply voltage is anything but well defined.

What you haven't said at all is what kind of precision you want to achieve. If all you need is 10% then a very simple setup is enough. If you need better than 0.1% then you need better analog circuitry.