Another big variable is day of travel. Most destinations will tend to have higher fares for Sun/Mon/Thu/Fri travel and if you check out the rules for WN sale fares they actually exclude travel on Sun/Fri. That said, leisure markets like LAS and Florida tend to have different peak demand days than business markets and the sale fares generally require Sun-Wed travel outbound and Tue-Fri returns for these markets. It also to important to pay attention to advance purchase requirements (generally 14-days) for lowest fares. You can find these down in the fine print. You can see an example with the current sale which goes through today for travel through May 20th --

https://www.southwest.com/html/offer...ginAirport=BNA

The current sale has BNA-MCO for $102 one way, but I'm seeing fares as low as $81 one-way on this route which you could use as somewhat of a benchmark. Though those $81 fares are generally only found in January when demand is pretty weak for MCO. I'd probably guess $100 one-way will be a decent price for summer travel when demand tends to be higher.