I noticed your name contributed on Familysearch.org. Are you the same Jim Pearson that did all that work on the Iowa Simonton's? Well done.
Although I'm a relative newcomer to the Geneaology scene, I've been trying to continue my Grandmothers work on our Scotish side that she started in the 1960's long before the Internet services (which would have been a huge help to her), and stopped at her death in 1987 at the age of 93. She was a retired Librarian. She had our French side pretty well nailed down now. Anyway the question I have for you. You mentioned an Andrew Simonton that came over in 1718. Which Andrew is this? This isn't the first time I've seen this, but this Andrew and this date are a mystery.
If you go to Familysearch.org, and click on Search for Ancestors, and go throught the motions with only the Simonton name, no parents, or spouse, keep the year range, and year blank, click United States and stay with all states in the box you'll come up with many, many Simonton's as I'm sure you've seen hundreds of times. Andrew Simonton #18 is the link to my branch. He was born in Maine around 1710, and married Elizabeth Cobb of Middleboro, Ma. Is LDS site wrong? My Grandmother had documented fact that this particular Simonton married a Cobb, but no dates to go by as she learned that the Falmouth records were burned in a fire when she visted the Portland region in the early 70's.
Another key for me is Andrew's father was named Andrew Simonton born 1671 (his father was named William), who married Ann Simonton on the LDS website. I cannot pin down/confirm (yet)if they were married in Maine, or in Scotland. The LDS doesn't have her real last name, but this Ann had been tracked down by my Grandmother to be Anna/Ann Douglass of the County of Lanark, born sometime between 1674-1677. He mother and father were supposed to be a Lord and a Lady. I don't know if this is true, or not. She had a brother named Archibald born sometime between 1670-1673
Thanks for your time. 10+ years is a lot of effort, so I'm sure you can help me.