Hopefully you travel pros can help me with this... I am looking at booking a one-way 1st class from PDX-SRQ thru ATL, the fare comes up considerably higher than if I price it out PDX-ATL and ATL-SRQ as separate reservations for the same flights. If I book them separately will Delta combine the reservation and let us check the bags all the way through? Any downside to doing it this way? Thanks very much.
While they will check luggage all the way through, there is no way to actually "combine" separately booked tickets. While they should work with you in the event of IRROPs and you miss your connection, it will not happen automatically. It would be wise to leave enough time between flights so that a minor schedule change won't cause connection to become uncomfortably short or drop below MCT. If you are willing to accept a layover of 4+ hours (which creates a stopover domestically), you can book the two fares on one ticket using multi-city search. They won't let you book the separate fares on one ticket if the layover at ATL is less than 4 hours.