Frame bags and such are great if there is no other way to mount cargo or if one plans to take on some technical trails. Otherwise a bike with provisions for racks is preferable, at least to my way of thinking. My younger daughter preferred a frame bag, but we also had to come up with an alternate water bottle mounting scheme (small frame).

Touring bikes are heavier than a race bred roadie, but when rider weight is included, the percentage isn't so dramatic. I've used mine for gravel grinding and unloaded distance rides, no problems. A CX bike, like the Volpe I mentioned earlier, will offer sharper handling and also weigh slightly less.

Brad