When I get chance I will show you where a RTC battery can be installed, an SD card and GPS receiver. The RTC battery will allow the android tablet to keep the time even when the main battery is removed. This will allow you to cache offline maps. At the moment the android tablet gets the time when it connects to the internet. If no network is available it will default to 12 o’clock. If this happens cached maps won’t be available because the time they downloaded will be in the future compared to the androids time.
An SD card will allow you to store more cached maps
UPDATE: Open the back of the H7000 and you will see a 2 pin mini JST connector called RTC, this is where the RTC battery can be added a 3v coin battery will do the trick such as a CR3032. The SD card will accept a FAT32 formatted SD card.
At present there’s no use for a GPS receiver however if the firmware was modded or the Andorid hardware/software was modded it could be possible to implement follow me mode.