2005 Highlander 4WD, 100,000 miles, automatic, 6 cylinder

This morning my Highlander would not start up. I jumped it and got it running but down the road, all the lights on the dash lit up and the speedometer jumped around. Highlander will not start up once stopped (it needs to be jumped again). Is this a bad alternator? bad battery? I am running an Optima. Any thoughts? Sorry for posting on a Toyota 4x4 site. My Highlander kind of is a quasi 4x4. I do own two other 4x4 Toyotas. In fact, it was funny relying on my old 85 4runner to jump my newer Highlander.


Thanks,
JARED