Currently comparing the two touch screens I have to see which will work best for the project. The two screens are:

• Tontec 3.5" screen model #MZ61581 which requires an install of Raspbian Wheezey or Jesse so I would need to change from my current Debian install.
• Waveshare Spot Pear 3.5" RPi LCD (A) V3

Both screens are resistive touch because that is what I had on hand.

I am also considering ways to implement the battery pack. There is a nifty device called BattBorg, but it uses IO pins and that might interfere with the screen install. I will get the screen in place first then move on to battery pack choices.