You will def need 2 rooms. There are some hotels that will allow a 5th person on a rollaway bed for an added fee but no place I know of holds 6 per room.
If you are on a very tight budget and just want a clean, decent place to crash for 1 nt pre-cruise, I would recommend getting something in the MCO area thru Hotwire. You choose what * level you want and it lists some (but not all) of the amenities offered at that hotel, and the price. You just don't find out the exact name of the hotel until after you buy. You should be able to get something decent for around $40-50 + tax per room.
Sounds scary if you're not familiar but as long as you keep to 3* or better, it won't be bad. The 3* we got at MCO was Wingate Inn, 3.5* is Sheraton, 4* Hyatt inside MCO.
2.5* are Comfort Inn, Amerisuites, etc.
Here is a great website that has identified many of Hotwire's hotels, people report back what they actually got after purchasing. They are good at IDing and answering your questions and have been correctly guessing for me approx. 7 times now.
www.betterbidding.com
btw, Priceline only guarantees a room that sleeps 2. We are a family of 4 so this is the only reason I don't use Priceline. Plus I like IDing all the hotels on my Hotwire search results, then choosing the best deal. lol! (the thrill of the hunt and all that...)
Be sure to enter total # of guests and 2 rooms so that you get enough beds for everyone and both rooms at the same hotel.
I don't know that I'd book a whole vacation this way but for 1 nt. it's great!
Good luck finding a great deal.