We used to manually generate crew rosters using Excel - narrow the columns to represent hours, use one colour per route and below the 'routes' part, you aligned the crews/crew members.
You could also enter set 'blocks' for crew rest/time off and, when it all fell apart, see at a glance how many crews you could juggle to legally complete the job. Don't know how many crews you guys have but we did it with 50+ at times. I'd like to see how you guys do it if someone wants to invite me for a visit
Simple and effective and didn't leave it to a computer to screw up. I also reckon an Excel whizz could fully automate it too.