Lots of good information on fueling and would reiterate to start fueling from start of race. It is good to set an alarm on the bike computer to remind you to drink/eat. For races I typically will have bottles of around 60-80 carbs and gels of 30 carbs each. Real food is difficult for me on the bike. I try to drink every 12-15 minutes and have a gel every 30 minutes.
Other suggestion is adding in long 3-5 hour zone 2 rides. I used to be similar and fade at the 2 hour mark. I have been doing a ton of long zone 2 rides this year which has increased my durability significantly where I now can go real hard for about 4 hours and then start to fade a bit but it is not a huge drop off like before. The other benefit is the long rides are a great way to practice fueling and finding out what works for you.