We did a 30 fixed when we moved to our town about 14 years ago but ALWAYS paid extra, about 10% of the whole payment (principle, interest, escrow) got added every month. We treated that increased amount as our house payment. We refi-ed a couple of years in because interest rates had dropped so much and got a 15 year fixed for about the same amount as the original 30 year fixed. We continued paying extra, same format, as before.
When we bought our current home in Sept. of 2011 we went with a 15 year fixed. We pay extra on this in the same manner.
All this paying extra was already in place long before we started DR. We are in a different place than you. Find out what is available. Check rates other places. When we bought in ‘11 our “home” bank where we had had a mortgage for 11 years could not TOUCH what we got at another bank where we have part of our FFEF. It pays to check around.