Computers, particularly when used in near-realtime, such as WAZE and Garmin's live traffic via SmartPhone Link, are useful for planning routes while on the road. In urban areas where you lack local knowledge, these tools are powerful but you need a reasonability test in your mind. All algorithms are subject to failure. Most optimisers produce a good result or an optimal result. There is a reason Google limits you to 10 locations on its routing. RouteXL does well will 100 locations but it is a good result, optimisation with that number would take until the end of time.
The possible routes in the classic travelling salesman problem expands as the factorial of the number of locations. Specifically (n−1)! / 2. For say 11 cities the combinations are almost 20,000,000. The factorial of 100 is
93, 326, 215, 443, 944, 152, 681, 699, 238, 856, 266, 700, 490, 715, 968, 264, 381, 621, 468, 592, 963, 895, 217, 599, 993, 229, 915, 608, 941, 463, 976, 156, 518, 286, 253, 697, 920, 827, 223, 758, 251, 185, 210, 916, 864, 000, 000, 000, 000, 000, 000, 000, 000
That is a BIG number but you only have half that many.