I am now training for IM FL - this will by my first full IM, so I can't say my training schedule is successful, but I'm feeling like it will be....
So....
1. I started my "official" IM training mid July for my November 3 race. But, I also did a HIM in June. So I started training for the HIM in early February for the June race. I took off the month of June with scheduled training (i.e. I rode, ran, swam as I pleased, not according to any planned schedule), and starting in mid July I got back into regimented training. I needed that month and a half off or I'd be super burned out by now. I know how my body reacts, esp by this time of the year (I usually do a late spring/early summer HIM) and I'm usually burned out by now if I keep training straight through the summer.

2. I do have rest days. You have to!! If I don't take a rest day, that usually burns me for the next week's training sessions. And after riding 100 miles on a Saturday, I'm not feeling like doing anything on a Sunday! And as others have said, your long days will most likely be on the weekends (if that works best for you) but you can always move the days around in a week for what fits your schedule. I like doing my long runs Thursday afternoons after work. For some reason, that works best for me, not on a weekend morning. I prefer my long rides on the weekends. Plus, every 4th week is a "recovery" week where I step back my training, sleep in, and just get in minimum mileage. If I'm feeling wornout, I skip the entire day's workout. I've learned over the years not to push myself during the recovery week, because again, I'll burn myself out for my heavy training weeks when I really need the energy.

3. Yes, I work a full time job. I have no kids, I have one dog, and a really supportive husband. He does the cooking in the house, so that helps me with my diet, and when I'm worn out and tired, I know I'll still be getting a good meal each night. He also rides the long rides with me, so I always have someone getting me out the door and motivating me along the way. As for my job, it's super flexible - as long as I work 80 hours every 2 weeks and no more than 10 hours per day, it doesn't matter when I come in or leave (within reason of course). So that really helps a lot.

Hope this was relatively easy to follow......let us know if you have any more questions. There's no doubt about it - IM training takes a lot of discipline and time. But I enjoy it, esp doing the long rides on the weekends. It's given me an excuse to actually sign up for more century rides this year and makes it more enjoyable to have different routes, etc to ride.