Based on Friel's terminology, my biggest limiter is aerobic endurance. To improve endurance, I'm going to make my early A priority race a 75 mile race. Would I be better off continuing with a Base 4 then a Build phase? Right now I only have time for the 3 base phases and 1 build. Would I be better off just staying in base and continuing the volume increase and then after the race start the build phases for the 20-40 mile road races in July and August? Is there such a thing as too much base, especially for a newbie? Thanks.