Hey there, Still!
I think you'll (both) enjoy your tandem. They're a lot of fun and make talking and sharing in the ride so much easier because of the proximity. Anto's right -- they're slower on the hills, but fast on the flats (a bit more than the wind and rolling resistance of one bike, but the power of two) and frighteningly fast downhill (my aged father and I took mine to 101kph pretty easily). It is a great way to match people of differing abilities: The stronger rider can get a great workout while the less able one can still enjoy the ride.
Tandems foster cooperation and no one gets left behind. It is really nice reaching the top and bottom of a hill at the same time!
The only real touring challenge I've had touring with mine is the limited space for two peoples' luggage. The solution proved to be a trailer (I made my own, it works fine). Beyond that is the difficulty in finding partners, though you seem to have solved that problem first (well done!). In a pinch, many tandems make reasonable solo tourers. I have regularly ridden mine on hilly 260km day rides and found it surprisingly good.
The only real downside? Your respective solo bikes may not see as much use.
Looking forward to seeing photos in the Forum gallery and ride reports too. If they are anything like your tour account, they'll be corkers!
All best wishes for lots of fun together and happy days ahead,
Dan.