I'd recommend taking your time at DisneySea as well.
But I'd also like to mention the After 6 Pass for TDL would be completely worth it if the only ride you got on was Pooh's Hunny Hunt. There's nothing like it, and afterwards you will be so glad you didn't miss it.
Besides, you'll have a pretty good idea by evening whether you want to stick around TDS until closing or venture into the other park. Just play it by ear!
(And be sure to let us know how it went!)