Since it's almost September and you're going to be kind of close to DM by October, it wouldn't hurt to mileage run for 8-10k MQMs to get to DM:

1) The benefit of the GUC will come in handy for any international trip you book at least a month in advance. I haven't had any troubles utilizing a GUC, yet (till DL devaluates them). The value of the GUC will outweigh the cost of the MR ticket(s) you decide to buy.

2) Same Day Co-Terminal Change. This comes in handy when flying out of SF, NYC, even LAX.

3) You will see a difference in your upgrade position. For what it's worth these days, it isn't as much, but better ain't too shabby.

4) Agents on the phone tell you secrets if you are nice to them.