There is a blue tooth version.  But, if you go to the park you need a laptop to work from with you.  I don't think you will get very far with a cell phone. 

I would take my laptop and smaller tablet and run it off the battery.  If you got the bluetooth tablet version and have bluetooth on you laptop, you are set.  However, I wouldn't want to too far from the laptop or someone might decide it would nice for them.  :-)

If cost is an issue, you could do the same with a USB connection between the laptop and tablet.

If you are talking about something totally contained in one unit, you want to look at Notebooks not tablets.   How they are with big graphics programs I don't know.  Wacom has notebooks too.