"v1rotate dot com" writes:

basically draw 3 boxes and do all the calculations inside within these
boxes. This will limit the fixes to calculate.

It's not clear to me that these regions can be adequately chosen from the
start (especially for long flights) but it certainly would simplify things.

Limit area #1 for your origin, area #2 for your destination (allow fixes to
be within these boxes so they can join to airways.)

I think these will need to extend well beyond the endpoints. As a worst
case example, consider a trip to an airport just on the other side of a
mountain that is too high to traverse directly.

jeres bustr and leoni could be dropped, since they are on same airways

Dropping seems dangerous. What if one of those dropped waypoints is close
to your destination? Will you pick that up later?

--kyler