There are some 160 asteroids and I don't want to plot a 160 point route manually, do I have any options here? Can I modify the max distance for a particular fleet?
Unfortunately the max distance is hard-coded.
You
could create these orders by editing the database.
You'd still have to decide what order to go in.
The only way it would be faster to do it this way is if you already know your way around SQL statements--in particular, using a text editor (or Excel) to make a long script to insert 160 rows into a table.
Actually, here's an idea:
There's a standing order "Move to Closest Rendezvous Point."
You could create a trail of these points on the map, and use this as your secondary standing order.
So the ship would try to survey the nearest body, but if none is close enough, it will travel to the closest rendezvous point.
Creating a trail of perhaps a few hundred rendezvous points is probably less onerous than creating 160 "survey asteroid x" orders manually (which requires you to transcribe the precise order of asteroids). Each point is just two clicks (once on the button, once on the location), and you don't have to be too precise with them. If each asteroid gap can be bridged with just one point, this might actually be super easy.