I would choose 4 days at DW and 1 day at Seaworld. We are going in November and my DH would kill me if we didn't go to Seaworld. He loves that park! We will be spending 4 days at DW, 1 day at Seaworld, and 1 day at Universal Studios. I can't wait; I've never been to Universal.
To the original poster: Regarding the grocery stop question: We book a Quicksilver towncar to pick us up from the airport. Roundrip is $90 for us - two adults and one toddler. They include a free 30 minute grocery stop at Publix, which is perfect for us since we like to buy snacks, water, juice etc. for the room.
Also, we don't drive in Orlando either. Last year we booked Mears shuttle bus to pick us up from the hotel to take us to Seaworld. It cost us about $14 per person roundtrip and was very convenient.
Hope this helps!