BOS-HDN is served direct by JetBlue and was often $314 round trip last year except maybe a few midseason weeks. Obviously doesn't fly every day. I cant imagine you'd save enough flying Southwest to make it worth flying to Dallas. Probably a bit cheaper flying through Denver though.
I got a message from JHMR saying BOS-JAC now has a direct flight via American but I've never heard of it before. Will have to look into that. Hate American but a direct flight would be worth it.
Edit - just looked it up and indeed American is firing up a BOS-JAC route in December. Awesome.