Include a few sessions in the AM running on empty and building up to 1hr.
On longer sessions start to introduce electrolyte drinks (ml/hr based on sweat rate and conditions) and your food of choice. Lot of debate on the type of food to train and race with ie fats, mcgs vs carbs. I've personally trained on bars and bread-based snacks, racing on liquid, gels and the odd bar (inc protein bars).
I suggest hitting a compromise and occasionally doing the long(er) sessions with products you intend to race with, while the rest of the time taking other snacks that you find more palatable. Just get the right amount of cals/hr and ensure most of the cals are carbs, with some protein for the longer sessions to reduce muscle atrophy.
A basic anti-oxidant pill will supplement the diet. You'll need more Vit C and E at least on the hard weeks, as they are harder to bump up on the diet than Vit A and selenium. You can get a cheap pill that covers all at likes of Tesco, Boots, etc.
Similar to Pete I dived straight into a big solo ultra experience by attempting to run the 170mile Offas Dyke in one go. I had a few friends ready to ease me through the second night, but the first 2 days and night would be all by myself. And I loved it - one of the best experiences of my life. Full moon, clear skies running through quiet countryside is quite an experience.
Unfort I damaged the knee 70miles in and spent the night sleeping in the back of a small baptist church, until I was picked up in the morning lol