Mixed Routing Calculations

[Nedra]

I don't know if this is possible, but it would help to be able to do Mixed Routing Calculations... Let me give you an example so you understand what I just was reminded of that I haven't asked for before:

Allan is moving a specialized trailer from a Nuclear Power Plant back to the manufacturer or company renting the unit.
The load starts at South TX Power Plant, FM521, Wadsworth, TX and ends at Frham Safety Products, 318 Hill Ave, Nashville, TN.
Shortest Routing is only 847 miles, and on easily traveled roads from start to Jackson, MS, but from there to Nashville, the roads are not truck friendly.
Quickest Routing is 959 miles,112 miles longer.
It would be better if the route could be run as shortest from the plant to Jackson, MS and quickest from there to Nashville so it would shift to the freeways there.