I have a 08 Heritage Softail and we ride two up. I have the optional passenger pillon ( wider about 14 " ) that my wife really likes. Just did a 4 day trip and have another 5 day trip coming up. We use the saddlebags for the routine stuff & then have a sissy bar bag for the rest. Works fine for us and we always come back having taken too much stuff.
I find the Heritage is a good second choice for touring compared to the true HD touring bikes. It actually becomes a really good all around bike, as its not top heavy, bike weighs less that the full dress models, making the bike a good city bike as well as a tourer when you want to use it for that.
I know it will sound strange but we tried out a Goldwing 1800 and the Heritage Softail at the same time, same day, same wind & driving conditions and we both agreed the Heritage was a more stable & easier handling bike and reasonably comfortable to boot. So far it has served our purposes well.