How to make SDCs into Mileage runs
I have searched and haven't found anything directly relating to this.

I will be a Delta Skymiles gold elite within a few weeks. I am based in MSP and I am hoping that on days I have flexibility to add additional miles to my scheduled flights via the free SDC feature. The goal is to hit at least PM if not DM.

My goal from this thread is for me to receive hints of how to best pull this off. I will start with a few of my assumptions:

Delta.com will provide a list of at least some of the routes
Matrix ITA can be to find potential routes
Expert Flyer (in paid mode) can be used to find officially how many hops and official connecting airports I am entitled to
Availability may be more limited since I am based in a hub
I assume that only hubs can be used between departure city and final destination.
Routing rules will apply (at least to the displayed the airline web site)


In case it matters (I don't think it does), I fly mostly on sLUT fares.
My basic question, what would be the best techniques to build a SDC that would hit the most airports or most total miles.

Lets say for example I have booked MSP to LGA through MEM (already extending the number of miles over the direct). Is there a way (assuming seat availability) to fly MSP-SEA (Alaska hub)-DTW-ATL-SLC-MEM-LGA.

I guess my questions are as follows:

How do I find routes that are not on the airline website?
Once found, is my assumption correct that I would need to use a phone agent to make this change?
What are my chances of success in using SDC in this manner?
Any chance to build stop overs into a SDC? If so, what are the limits?
Are there maximum number of stops that can be accomplished? If so, is this based on fare type?


Thank you very much for your help.