It sounds like you need a cyclocross bike or a touring bike that can accommodate wider tires. I, myself, have a touring bike that gets mistaken for a 'cross bike all the time. I have the Kona Sutra. Kona's cyclocross bike is the Kona Jake the Snake. Specialized has a very popular cyclocross bike too. I will let one of the ladies here who own won speak to that. I ride like you do. I take it off road sometimes and I needed lots of gears for my bad knees. I don't care how long it takes me to get somewhere, just that I finish, and I wanted to do endurance rides like you did. I just wanted a bike that would let me do all that, have eyelets for racks, tons of gears for my bad knees, with wider tires to let me go off-road. My bike is heavy as it is steel but it is a smooth ride. The Specialized looks like it is aluminum if I'm looking at the right bike. I definitely think a cyclocross bike might be right up your alley.