Classic & Vintage - Schwinn Tandem woes...

So I finally found my self a tandem. It's a Deluxe Twinn 5. It's really clean and most importantly a workable size for me and my GF. It's got a few problems mainly horribly untrue rims and the stokers right crankarm is bent. I've bent it back reasonably well but the cranks are one piece which I hate. The rear has the Atom drum brake and a 5 speed freewheel. The rims are steel S-5's (which sucks). So this is what I'm thinking:
1) Bottom bracket conversion and then bolting on a couple sets of TA Pro 5 Vis cranks I've got laying around. I'll need a couple chainrings but that's OK.
2) Swapping for 700c's...... I bolted a 700c wheel n the front and it clears the fenders with a little room to spare so I can stick a bigger tire in there. I have not tried the rear but I assume I'll find the same result. Problem is....The rear has no provision for a caliper brake. Should I re-use the Atom drum? Is it still serviceable? I was thinking about lacing up an internally geared hub with a drum brake. I've got an old SA 3 speed with a drum brake that is really clean. Would it have enough stopping power? It is a lot smaller so I doubt it. Should I look for something newer? Maybe a visit to a frame builder for some canti bosses and a fork swap is in order so I can have canti's on both ends and a rear drum as a drag brake.......
So what do you think? Am I crazy for wanting to upgrade this thing? (Haven't ridden it yet either)

I had a deluxe twinn and I have a few opinions on some of your upgrades. I liked it, my girlfriend loved it, because we could cycle around and she didn't have to navigate through traffic on her own. She usually looked at real estate as I 'biked' up front. We cruised to cafes, the park, the beach, and so on.

It isn't really a performance bike. Alloy rims seem like a waste of time. I don't think an SA-3 is hearty enough to handle near double the torque, you rarely see them on tandems. I don't know about the SA-drum. I do know about the atom drum brake, it's Fred Flintstone brakes at best, but did the job for our combined 350 lbs. The magic of the drum isn't stopping power as it is its durability.

With what you have I would true and tension the rims, replace the stokers crank, button it up the best you can and try it out with your significant other and see how you and she likes it. Then You can access what you have, how it works and what you may want to upgrade.

I agree with the above post. What you have is a solid steel unkillable tandem. I don't think that it is worth , if it is at all possible, to put a 3 piece bb conversion kit to change to a cotterless crankset. Plus putting lighter wheels on this all steel bike is not going to make a big difference. The Atom drum brake is bombproof-leave it as it is. I have never heard of using an SA hub for a tandem wheel-not sure if it would be strong enought for the power of 2 drivers.

Thanks guys.....I guess I'll just try to get the wheels trued up and keep reefing on the crank arm until it's good. I've already gotten it clear of the chainguard so another 1/4" should do. New cables, chains and seats and we'll give it a whirl. If we like it then I'll upgrade.....

Oh and conversion kits are cheap and work just fine....PastorBob and Stringbreaker both have fine examples of how well they work and perform. I've tossed a handfull of them myself at BMX's back in the day.....Thanks again for the sound advise!