The most important race of the year for me is the 1/2 IM in Lubbock. The race is very hot, flat with 8 very steep but fairly short hills on the bike. I've got enough running and swimming experience to accurately predict my abilities and finish times. However, I've got no clue about the bike.

Does anyone have suggestions on what kind of milestones I can set to know that I'll complete the bike leg in my goal time (under 3 hrs)?

I've been completing 65-75 mile rides followed by a short run for several weeks. In the coming weeks I'll maintain the 65 mile rides and start lengthening the run.