You will be over your payload (and possibly other things) with proper pin weight. Dry it looks to be 2611 per the Forest River website. I think you might be better served with a DRW for a 40' 5er TH.
In your initial weight calculations for the trailer, you are forgeting a lot of things:
-Clothing/riding gear- can add as much as 200lbs depending on how long you pack for and how many people.
- Camping gear (grill, chairs, tables, games, etc.)- Could be another 200lbs there.
- RV gear (chocks, leveling blocks/pads, sewer and water hoses, tools, etc)- Depending on if you are Herk or not
might be another 200 lbs or more.
- Other necessary household items (pots/pans, utencils, cleaning supplies)- Maybe another 50-100 lbs, again depending on what you use or need (I like my cast iron for camp cooking, but thats a lot of extra weight for pans)
- Entertainment items (DVD's, board games, kids toys/games)- Maybe 25-50lbs more there.
Another possible 750lbs[<=edited for poor mental math] of unaccounted weight there, and with a big monster 5'er like that, there is a lot of places to store stuff, you might not realize you even had that much in there.
Just some things to throw on the thought table. Personally, thats pushing it closer than even I (borderline with my TT/TV setup) would dare to go. However, it's your choice and your safety, so it's ultimately up to you to weigh that out (pun intended). In any case, be safe!