As with backpacking and bicycle camping, I have found out quickly that for two-up touring on an Airhead less is most definitely more, be it in mass or volume.
It doesn't matter if I plan to find a campground on my motorcycle or pull up to a quaint bed & breakfast; space in and above the saddlebags for two people's essential belongings and luxury items is at a premium, and weight management and distribution is key to preserving your bike's handling on the highway -- especially with a passenger.
With whatever you bring, keep the weight low and to a minimum. Stuff that squishes is bad. Stuff that wiggles is worse...
I use the same L.L. Bean tent I have used for years for backcountry camping and "bike-packing". It is a three-hoop trapezoid-shaped model, wider toward the door and rated for three friendly individuals (or two and lots of gear). The covered vestibule gives you additional dry space outside the tent for dirty items like packs or boots. A quick check of the Web suggests that Bean currently only makes a solo and two-man version of this tent, but both are lighter and pack smaller; the Microlight #2 tent ($149.00, 32 sq. ft.) is 4.5 pounds and packs down to 7" D x 24" L.
As for sleeping bags, I find any good-quality synthetic-fill backpacking bag rated down to 15-20 degrees is good for a wide range of conditions; look for one with a carry weight of 2.5-3.5 pounds. With the aid of an aftermarket compression sack, you should be able to mash your sleeping bags down to the size of a large loaf of bread, perfect for lashing atop a rear rack or saddlebags (if you are want to carry two bedrolls).
When I bought my second Airhead last October, I flew down to Oakland from Seattle one-way to meet the seller at the airport. I had to have carry-on luggage that held tools, clothes, and personal effects for a rustic two-day cycle trip back up the West Coast, knowing that I needed to be pretty much self-sufficient while riding a bike with no saddlebags. I chose the Helen Twowheels Super Packing System with a medium clothes sack and a medium roll-top sack.
The system consists of a set of straps that loop around the rear subframe under the bench seat and allow you to securely cinch down the specially designed weatherproof compression bags without additional bungees or cargo nets. These two bags and my magnetic tank bag held everything I needed for the trip (tools, extra leathers, clothes), and the strap system anchored everything to the pillion in rock-solid fashion. I leave H2W strap sets in place on all my bikes now, ready for an unexpected load. I can't recommend this product line too highly.