Dear Quadsplus1,
You didn't say whether you were trying to exchange into an all-inclusive, or purchase an all-inclusive vacation from a tour operator, ie., Apple Vacations.
If you are looking into an exchange, many of the Dominican Republic resorts, and Riviera Maya resorts (and other Caribbean Islands as well), have either mandatory, or voluntary all-inclusive packages. Some are of the opinion that rather than exchange into a mandatory all-inclusive resort, it would be better to purchase a package from a tour operator. I haven't run the numbers, but there are two resorts in the Dominican Republic in Punta Cana that I've been looking at: the Melia Vacation Club at Melia Caribe Tropical (RCI#5476), and the Melia Vacation Club at Paradisus Punta Cana (RCI#4119). There are reviews of both in the TUG Resort Reviews, and the mention of the all-inclusive fees (at 2003 prices) of $50 per day per person for Paradisus and $30 per day for Caribe. Not sure what current prices are, or if there are discounts for age (usually), but with some research you might be able to tell. Reviews are decent, and both have 1 brs that sleep 6. Not sure how many units there are, nor how easy it is to exchange into, but it's a start.
As for getting there, Apple Vacations, has an in-house airline
www.usa3000.com that has regularly scheduled flights to Punta Cana (and other destinations in the DR and Mexico), particularly out of the NY/NJ airports, that you can reserve seats on, you need not have purchased one of their packages.
If you run the numbers for your situation between an exchange, the all-inclusive fees (particulalry if children under 12 are discounted), and the airfares, and then compare them to what you would pay for a tour package, which likely would be hotel room, so you'd be either cramped, or have to pay full (grown-up rates) fare for 2 of your children and get two hotel rooms, you might find that if you can exchange into some all-inclusives, you'd be ahead, plus have the benefit of the roomier timeshare.
Good luck.
Nick Roseto