We have stayed several times at OKW and used the boat to DTD. The boat has never been crowded and the captain always let us keep our son in the stroller. Right behind the captain is the handicap section. The seats pull down or push up. You can sit on one side and the small strollers fit just perfect in front of you.
This is (of course) only if there isn't anyone who would need the handicap section.
When you dock the boat you have to go down a few steps. There is a ramp that you can push the stroller down it is located near the main pool.
Have a great trip.