CCM . . . ah yes!
Best bet sell the CCM; then buy a USED tandem with at least 18 to 27 gears (yes that many gears available nowadays on tandems!). Your pocketbook will dictate how much to spend. But I have seen pretty nice used Burley tandems for under a $1,000 (US).
Looks like you are used to upright bars on the CCM. There are mountain bike tandems (upright bars) and road tandems (drop 'racing' bars). Your choice.
But if you'll be touring, definitely at least 18 gears . . . as you say the CCM 3-speed doesn't cut it. These later model tandems can be half the heft of the CCM.
Putting a tandem on plane is whole other issue. All airlines, that we know of, mandate that the bike will be in a box. Go to your bike shop and see if they have tandem box . . . if they do not, see if they'll give you TWO regular bike boxes. Those can be spliced together. Some airlines will supply a box for a single bike only . . . ask for 2 boxes and do the splicing thing. This will entail partially disassembling the bike (take off pedals, maybe one wheel, turn the bars, take of the stoker's bars, etc.). And some airlines will charge you quite a bit extra to fly the tandem! There is a specific maximum length of box that the airline allows, check with them.
Climbing: With a minumum of 18 gears you will be able to climb; yes, both of you will have to work, but that's part of TWOgetherness!
Hope this is of some help! Retirement is great . . . enjoy!
Pedal on TWOgether!
Rudy and Kay/Zonatandem