Turbo training programs for long distance events Can anyone suggest good turbo trainer workouts (or tell me what features are necessary) for training for a long distance cycling event (Vätternrundan ~300 km)? 

I need to be fit enough to cycle that distance but also need to get my raw pace up because of a tough target time (8 hours requiring about 40 km/h [in a group of 28 riders]) - what sort of drills should I be doing (or what should I avoid) to increase stamina and power efficiently?
Turbos are great for short interval work, brutal power workouts (cf. the comment above citing sufferfest.com) where you can monitor your output and heart rate more accurately. But they are dull, mind (and body) sappingly dull. 

I'd save the long workouts for the road, it's more interesting and you've got mates to chat to and spend time with. 

Use the turbo for working on the raw pace, short (60-90 minute) pieces with shorter, harder threshold pace intervals.