I wired up a DS18B20+ probe directly to GPIO4 on my Raspberry Pi 2 as per the following instructions: https://raspberrypi.stackexchange.com/a/48360
I then added OneWire support based on the following as well as installing kmod-w1, kmod-w1-gpio-custom, and their dependencies: https://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing/ds18b20
Now on to graphing.
I've had success with RRDTool in the past using these instructions based on Perl, however the collection method depends on the use of DigiTemp and unfortunately DigiTemp relies on a serial input device vs. direct GPIO access.
I tried the Python script supplied by Adafruit, and it worked well, however I'm not much of a programmer and would still need to learn how to output the results to RRD.
I then stumbled upon luci-app-statistics and found the collectd-mod-onewire plugin. It's an experimental plugin and marked broken in the OpenWrt makefile. I removed the @broken tag and it appeared to compile without issue for the x86_64 target. I tested this in Virtualbox, adding "--fake=10" to the owfs command, however could not get a proper plugin wrapper automatically written to /etc/collectd.conf from the luci-app-statistics UCI file.
I really like the idea of getting this working in luci-app-statistics if possible, but am definitely open to suggestions. Thanks!