Congratulations on the trainer century. I find that doing long distances on the trainer is made much easier by having a virtual reality trainer like the Tacx or Elite - your wheel speed controls the rate the real-life video on the computer screen advances, and the amount of resistance matches the gradient of the road shown. As well as real-life videos taken of classic routes, there are virtual reality courses that have lots of fun features to keep you entertained. I can't imagine doing a trainer session without having anything to look at or motivate me to keep going like this does.