Originally Posted by mountain-biker
Any thoughts?
If you've been successful with the trail-a-bike then the tandem would probably work out well for both of you...
Best bet would be to look for a used or NOS Cannondale MT800 from around '01/'02; that would be a great bike for what you're considering.
However, with regard to the three bikes you are looking at, here are my thoughts:
Schwinn: If you're buying from a brick & mortar bike shop in the local area (aka, LBS), theN you "may be OK". What you're looking for is a bike shop that's got enough experience with the Pacific Bike (parent company) era of Schwinn bike production to understand how well they hold up, who can provide service, and who are tied into the warranty program. My take on Schwinn's bikes are, frames are probably OK; mass-produced in Asia using time-proven materials and technology. However, where I'd be more concerned is the hubs, headset, brakes, and fork. The hubs (Quando) could be good sealed cartridge bearing models or they could be not-so-good unsealed loose bearing models; Quando makes a full range of hubs for many different brands. Same thing with the headset. The brakes, there is only one "tandem-rated" mechanical disc brake available aftermarket... Avid's BB7. Now, others have used different mech. models of Hayes brakes with good results; but not this particular model. My concern would be having high expectations for what looks to be a light-duty disc brake. Same thing goes for the RST fork. Both of these products are basically entry level products used on single rider mountain bikes targeted for easy to moderate useage, not heavy-duty applications. So, while the "package looks" ready to rip it up, I'd be careful about how hard I'd push it.
Burley: The best thing about a Burley (or Trek) is that they are only sold by pretty good bike shops, something I find somewhat reassuring. They may not be tandem experts, but most shops that carry Burley products are usually staffed by qualified mechanics. As for the bike, the Zydeco has come a long way from it's early days an unimpressive steel "family tandem" that flexed more than Arnold S. The aluminum model is spot on for the target market (entry level) and the components are higher quality than the ones found on the Schwinn. While it lacks a suspension fork and disc brakes, the benefit of that is that it doesn't lure you into more aggressive riding than might be prudent, particularly considering your precious cargo. Remember, the stoker on a hardtail tandem takes the brunt of most bumps. Therefore, while the captain clearly benefits from a suspension fork, the stoker tends to get banged around. A suspension fork and disc brakes could easily entice a captains to ride the tandem more aggressively than they would if it was a rigid bike which, as you would expect, brings with it higher risks for more violent crashes and increased wear and tear on the riders and the equipment. So, consider that a rigid tandem could have a nice moderating effect on your riding habits.
Trek: Clearly targed towards "family use" on paved multi-use paths and/or crushed gravel trails. Components look to be OK, on par with the Burley. Comments on Trek dealers are noted above in the Burley section.
Bottom Line: The Schwinn could be right on target for your needs. However, you'll want to be sure that yoru dealer will stand behind the bike with regard to free tune-ups and any warranty work that could be required. Again, while it has a suspension fork and disc brakes, they are more show than go in that they are not necessarily intended for use on anything that is too aggressive. The Burley is a solid product backed up by a pretty good dealer network and very good manufacturer support/warranty. It will support your riding needs for several years to come and should have fair resale value should you decide to sell it. The Trek, it's a good product but I don't think it would be my first choice for off-road trails. Otherwise, it's on par with the Zydeco for dealer backing and perhaps even resale.
On stoker kits, bear in mind that stoker kits raise the riding height of your child. Now, if the tandem's stoker compartment is short enough, there are crank shortners that can be used for young riders that reduce the effective length of the cranks to be more proportional to a child's short legs. The latter is the ideal situation for off-road tandems.