I realize that there are many factors involved, but are there any general guidelines as to how long can someone go once they go past their lactate threshold?
I realize this involves complex issues of environment, pacing, speed, but are there any hints as to parameters once a rider starts into the red zone?
An example woud be at the end of a crit, setting up for the finish how long can I expect to be able to push once I'm anaerobic?

IIRC, at VO2Max about 5-6 minutes; above VO2Max, depends on the amount of force you're producing--the more force the lower the time. The time can be influenced by your tolerance for pain and fatigue and by your motivation.

If you are training with power, you can use the following information to determine how many matches you have and how hot you can burn them at before you run out:

https://www.cyclingpeakssoftware.com/power411/match.asp

Thanks NoRacer,
that's a cool link, I have that book and that software but never found this info.
your IIRC info is also useful.

There's no general rule for how long you can last above thershold, but you can get a good measure of how much work above threshold you can do. If you have access to a lab with a gas analyzer, you can gt your max O2 deficit measured which will tell you the total amount of work you can do anaerobically. Then it's just a matter of how you meter out that limited energy. Go only a little above threshold and you can last a long time; way above and your time is morel imited. You can get a reasonably good approximation by calculating your anaerobic work capacity as described in this article. https://www.velo-fit.com/articles/critical-power.pdf

I asked a similar question a while back...
Friel has a very general chart in his "bible"...from a flawed memory the quality of race-fittness is indicated by excellent, good, average, and poor. Excellent was >4-5min above LT; good, 3-4> above LT...or somewhere around there.

As everyone else has said, however, it depends...asgelle sums it up nicely/informative article if training with power.