Most rooms at the Dolphin have two double beds. No couch or pulldown bed. They will bring in a rollaway bed on request and these are quite large and comfortable, even for an adult (I've slept on one and I'm 5'7"). There is a charge for this--I think around $20 per night.
If you have Marriott or Springwood frequent visitor status (definitely for Gold and Platinum, I'm not sure below this level) there is no charge for the rollaway beds. They also guarantee an upgrade if one is available. We stay at Swan/Dolphin a lot and have sometimes been given a suite. Last month we got the Vice-Presidential Suite, which was really something! So it doesn't hurt to ask if an upgrade is available.
Since the beds are doubles, everyone might have more space if one adult takes the rollaway, and the other adult shares with the smallest child. But I don't know what your family makeup is, of course. The double beds are small, but the rooms are spacious enough to easily fit the rollaway without cramming, and it flips up against the wall in the day for more space.
We are a family of four, and when we stay at the Dolphin, husband (6'5") gets a bed to himself, I get the other bed, teen daughter gets the rollaway, and son sleeps on the floor. He is young and has no trouble sleeping ANYWHERE, so comfort is really not a concern for him, haha. If you have young kids who don't mind floor-sleeping, this is always an option. The Dolphin will provide extra blankets if you ask. I know sleeping on hotel floors is not something that some people like to do, but we're kind of laid-back that way.
If we're at the Swan, usually husband gets a bed and daughter and I share the other queen, leaving the rollaway for our son, but half the time he just chooses to sleep on the floor anyway, leaving the rollaway for his sister.
