That is a very heavy tongue! The Class V receiver on my F250 has a max dead weight tongue of 600lbs, and can go up to 1200 lbs with a weight distributing hitch. (Class I is up to 2,000lbs, Class III, 3,500, Class IV, 5,000 and so on)

Not trying to flame you, just want to make sure you have your info right and you are safe going down the road.

Are you sure yours is that heavy? For good balance, a trailer's tongue should be 10-15% of total trailer weight. So that is 200-300 lbs. for your trailer.

I just looked at some Rockwood PU's on the Forest River site and they all have much lighter tongue weights than you are quoting for yours. Here's a random floor plan and specs:
Rockwood Floorplan Here's the page with all current Popups and their weights

If you have weighed your tongue and it is indeed 700lbs, then that little 4 bolt hitch is totally inadequate. But it is unlikely that it does weigh that much.

Here's a link to the RVnet popup forums, you can learn a heck of a lot about towing from these guys, most of them are pretty nice.