I'm fortunate enough to not suffer from severe cramping or bleeding, so I can't really comment there. But I have had success with acupuncture to help with the cramping I do have, to the point where if I keep up with regular acupuncture, I don't have any cramping at all and my periods are more tolerable all the way around.

Also, in the past I have had the same timing issue that you are having related to an Ironman event. I also cannot tolerate most BC pills and don't like to mess with my hormones. But, my doc worked with me and got me on a low dose BC pill where I took it consecutively for 6 weeks (I think), about 4 months out from the race. That was enough to shift my cycle by about 10 days, problem solved. Meanwhile the low dose pills for a short duration were no big deal and the effects were way out of my system by the time the event came.