Thanks. If no one provides any keyboard recommendations I'll probably just buy one and try it and I'll try to remember to update this thread.

In the past I have:

1. Created a blank spreadsheet for records in Excel
2. Printed it off
3. Filled it in by hand in the field
4. Took pictures and stored them in DropBox so I could have an electronic copy again (sometimes forcing me to drive a long ways to find the sprayer because I forgot to do it while the sprayer was nearby)
5. Re-typed the data again in different spreadsheets for billing purposes.

Just seems like a lot of those steps could be eliminated by keeping it electronic all the way through.