Southwest lets you check FF availability on-line, with preferred dates/itinerary, using their "SeatFinder" feature.

This feature should contribute to a lighter call volume at the RR department.

With the current system on Midwest's site, you can only check a three day time period, before you have to try other dates. It can be very time consuming, for those not calling in to MM.

I am not familiar with the award travel booking logistics on the Frontier site, but I assume it gives you a one-week glance, as its booking engine does for paid travel.