It's really tough, isn't it!
We booked DVC for Nov about ~ 7 months ago and I started checking airfares daily and then twice a day, so I can tell you what's been happening during that time. SWA has had some great Ding specials ($105-$130-$150), but they usually don't start to offer them until ~6 weeks before. You can always book and then get a credit if you find a lower rate. That said, I checked the SWA site to be sure that flights for your dates are wide open ---the lowest fares are still available. If the lower fares start to book up, there might not be much availability for a Ding special. Are you willing to gamble and wait until late Nov or early Dec to see if there's a Ding?
Delta hasn't seemed to offer real "sales". In the last 7 months, I read on this board on two occasions that people got a good rate from BDL to MCO, but it was only available for 24 hours or less. I got lucky myself, and happened to find tickets for $148 RT (we stop in Atlanta going down and have a direct flight coming home). I consider this pure luck that I happened to check at the right time. This rate was only available for a few hours. I haven't seen anything remotely close to a rate this low since then, and I usually check daily.
I think that USAir and perhaps United have had some sales a few months ago (for ~ $160 RT), but they don't offer non-stop flights, so I don't usually pay much attention to them. The current flight that stops in Atlanta will be the first time we haven't flown direct for at least 5 years. But, I'm not willing to pay hundreds of dollars more just to fly direct.
So, I'd suggest you keep checking Delta several times a day and you might get lucky, but that's not very reassuring (and Delta hasn't had a history of sales in the past 7 months). Or gamble on a Ding, or book SWA and hope you can get a credit because you'll find a Ding or they will have a sale ---- this isn't a great plan if you or a family member/friend can't use the credit within the next year.
Good luck! DH wants to go to Tampa for a weekend in Dec and fares are at least $250, so I've got a similar situation.
Edited to add: If you really want the comfort of a non-stop flight at times of your choosing, the extra $$$ spent can be worth it to your peace of mind (unless it's pinching the pocketbook so much that it creates other worries!). If you choose to book SWA, at least you could be eligible for a credit if/when there is a lower rate (which I'd expect will happen with SWA, especially since you're not travelling at a busy time) ......... and you'll be able to pre-board if you have an infant, so the lack of assigned seats won't be a stressor.