The only tandem "dealers" in the Atlanta area are:
Bicycles Unlimited in Peachtree City who is an authorized dealer for Co-Motion and MTBTandems.com in Canton who caters to a world-wide market of off-road tandem enthusiasts via the Internet. At the moment, there just happens to be a $3k Trek T2000 hanging in the Marietta Free Flite that belongs to one of the managers. Both Atlanta Cycling (Cannondale & Santana) and Bicycle South (Burley) took a shot at stocking tandems a few years back but quickly decided to drop back out of the market.
As for dealers who sell the brands you are looking at....
There are -- at least according to Raleigh's Web site -- four authorized dealers around Marietta which you can see by loading this URL:
Coincidently, 3 of these dealers are also Diamondback dealers as are the Silver Comet Depot & Gaylans:
Here are your Schwinn dealers:
There are a few KHS dealers around Atlanta:
I would be surprised if they had a tandem in stock but, you never know. Give them a call and see what they can do for you. Perhaps they would be willing to obtain a demo from their distributor for you to test ride.
The entry level tandems for the various brands are:
Trek - T900 @ $879
Raleigh - Companion @ $680 / Coupe @ $1100
KHS - Sport @ 769 / Comp @ 1199
Diamondback (Pacific) - Wildwood @ $660
Schwinn (Pacific) - Tango @ $549
There are some others, but for the most part the entry-level offerings are all similar products that are fine for the type of riding you describe. The frames are not light but they are durable and will outlast most of the components. It's critical to be sure these types of bikes are functioning properly when you take delivery and that you take them back to the dealer for what is usually a free 60 day / 50 mile tune-up as attention to derailleur, brake, and bearing adjustments will be needed during the break-in period. So long as these preventative maintenance tasks are taken care of, including your own bike cleaning and chain-lube routine, most "teething pains" will be quickly resolved and these bikes will remain somewhat trouble-free so long as they are used for the intended purpose.
As for taking on the more challenging terrain, the somewhat more expensive ($1100) models would be lighter, have better wheels, and wider gear ranges that do lend themselves to more adventurous outings. Again, nothing at this price point is going to be "chi-chi" or high-end, but with a regular maintenance program these bikes will certainly meet the needs of any family that isn't racking up 1,000 of miles of riding per year. Once you start getting into the mega-miles, it just makes sense to start looking at used, low-end models of tandems from Cannondale or Burley that have sealed bearings on the bottom brackets, wheel hubs, and headsets. The following is what I'd call a "best value" and a GREAT first tandem, assuming it would be the right size for the captain (no relationship or personal interest mind you...).
FOR SALE 12/07/03: 2002 Cannondale R1000 Size M/S - Horizontal TT length captain is 21.5"/54.6cm, horizontal TT length stoker is 27.1"/68.8cm for more details see: http://www.cannondale.com/bikes/03/geo-13.html
This tandem is Nantucket Green. We've ridden it about 3000 miles and have decided to upgrade. This tandem comes with the following non-stock components- Ultegra Crankset,Thomson Stem and Seatpost, Continental Tires, XT Cassette. Asking $1,200. I live in the Boston area and can deliver the bike via car in the New England area. Otherwise buyer pays shipping. See links for pictures: http://www.stompnground.com/bikepics/tandem_001.jpg
Home Phone: 508-650-1945
As for long-distance purchases, your cost estimate on shipping is in the ballpark and the assembly fees also sound reasonable. If you have a good LBS where you know the owner or manager(s), your best bet is to work out a deal where the tandem will be shipped to their shop vs. your residence which will save a few bucks on the shipping, plus it gives them the ability to check-out the bike for you as part of the acceptance end of the deal. Most small shops that I've frequented don't mind offering this kind of service for a nominal fee in the hopes that their good service will bring you back for your accessories, clothing, and future maintenance needs.
Keep us posted on your progress....