Whether you are insane or fooling yourself depends on how far you have ridden before.
Doing this in four days would be equivalent to riding PBP. If you haven't done a multi-day ride, let alone a 600Km ride like that required for qualification for PBP, then you are unlikely to complete this ride in four days, let alone do it again a few days later. In fact, doing a second 1200 Km ride three days after the first would be an extremely impressive feat. You should consider RAAM in such case.
I suggest that before you attempt this ride with such an aggressive schedule that you go out and do a 600 Km ride in a two day period. As you finish the 600Km, ask you self if you are ready to start out on doing it again.
As far as your packing list goes, you don't have any change of clothes. You should carry a second set of clothes. What will you do when it rains and you are soaked (rain suit won't prevent you from being wet). You list no toiletries. Do you not wash, comb your hair, brush your teeth, etc.? What about a sleeping bag and sleeping pad to go with the bivvy? Will your bike light serve as a flashlight? Maps? Phone or calling card?