I have to tell you I don't recommend it. Especially, that much (5000#) over the limit. Many around here believe the tow limit for the motorhomes is due to the extension AS added to the P30 and it has more to do with lateral loads than toungue weight limits or the power of the engine/tranny combination.
While a few have even made modifications to the chassis to tow more, I think the most the P30's were rated for was 4000# (maybe 5000#). It's not can it pull it, it can, it's what happens with someone pulls out in front of you on a decent in the mountains and you need to panic break while swerving out of the way. Also, since these guys are pulling close to their design limits just going down the road...adding another 50% of the weight of the motorhome is not doing your powerplant any favors.
While the AS's have many positives that make them like no other motorhomes, if you need to pull 7000 lbs I think you're looking at a used diesel pusher...not an Airstream Classic.
1986 Airstream 345 Classic Motorhome