Thank you all for the feedback.
If an internet connection exists then yes many good resources are available to read, study and research.
The Kindle costs little more than $100, the battery lasts for weeks, the display emits no light and reads like paper. The format was developed at after many attempts to display as much information as possible in the display area of the kindle. It does a good job of intra-text searching and I have been able to format a parsing dictionary and a copy of the LSJ for the device as well.
I generally am not moving back and forth through the text when I read but sometimes must return to a previous section to clarify the reference of a pronoun etc.
At my age I find that In order to make net progress in the study of Greek I must study longer and hopefully absorb more than I forget
. This device, My android phone, along with conventional materials allows me to do this.