I'd say if you don't need a kitchen or kitchenette, you shouldn't discount splitting up the party into two rooms (that might wind up connecting anyway).
First of all, with a room of 5 people, 4 of them over the age of 17, if you're going to be honest with WDW about their ages, you'll pay an extra 50 dollars on top of the cost of the room. Room rates are based on double occupancy, but deluxe resorts seem to charge 25 bucks for each additional adult after the first 2 adults. Children 17 and under staying with parents are no additional charge, so the 16 year old is free. But the 18 and 26 year old in the same room will cost ya.
Now it looks like the least expensive resort, during Value season, would be the Contemporary Garden Wing, 280 a night, plus 50 for the 2 add'l adults. SO, 330 a night for Value season (I don't know when you're going)
In comparison, TWO rooms in a MODERATE resort during Value Season would be 300 a night. For that, you'll have more room and TWO bathrooms. What you'll be giving up is (potentially) prime locations. Since the Contemporary puts you within walking distance of the MK, and the monorail can get you to TTC for a monorail ride to Epcot...well, you have to decide what the value for that is to your family.
Again, the Contemporary is the LEAST EXPENSIVE Value resort that can accommodate 5 to a room. Beach Club, Yacht Club, Boardwalk start at 385 for 5 people (4 adults) in a room, $405 for Poly, $450 for GF, all of this Value Season pricing. Animal Kingdom & Wilderness Lodge only accommodate 4 people each.
Some other options would include staying at the Cabins at Fort Wilderness (sleep 6 starting at 265 a night, but only one bathroom and the full kitchen you say you don't want), or staying at the Swan or Dolphin. Neither one of these resorts is an official Disney resort, but they're both walking/boat distance to Epcot and the Hollywood Studios (something in which you expressed interest). You'll still get Disney transportation while there, but I don't think you can use Disney's Magical Express, and if you have a car, you will be paying extra for parking in the hotel's lots.
One final thought for potentially saving money would be if one or two members of your party got an annual pass. Annual passholders often get discounts on rooms. You'd only need one person to get an annual pass if you were going to get all 5 in a room, 2 people will need Annual Passes to get discounts on two rooms (I believe this is the case; in the past, one annual passholder could book up to three rooms at a time, but I think now, each room has to have one passholder).
Good luck, hope that helps.
EDIT: Just went to the Swan/Dolphin's website, and they have a special deal throughout the year - book one room, and the second room for the same time is only 99 a night.
