The essential elements for touring are Sleeping gear: I.E. tent, sleeping bag, pad, headlight. On the bike/ off the bike clothing, footwear. Hygiene kit Tools spare tubes etc... electronics... and then there is food related stuff like the stove? and the amount of fluxuating amount of food you have at different times. Most people max out getting their gear to fit on a single. On a tandem you need to fit another sleeping bag, pad, twice the amount of on the bike/ off the bike clothing and a second hygiene kit and more food. You simply run out of room. I would suggest that you give it a try and outfit your tandem with enough gear for two (using ft/rr panniers), and see if you are able to get it all to fit. Maybe you can tour with less gear and can make it all fit? Good luck.