Redroger,
I've seen many of your references to "Luffman" in America over the years, but this is the first time I have noticed a specific area (Virginia), name (Daniel, son of James), and timeframe (after 1650s) mentioned. This does help. Here are some things you might do:
1) Look at internet for early Virginia settlements. Nearly all were on the James River and spread out from there. Henrico County was a major, early population center, but see
http://freepages.genealogy.rootsweb.ancestry.com/~harrelld/va__county_chart.htm County names changed often in the early years as large counties were sliced and dice to form smaller ones.
I have all my earliest (found) paternal ancestors showing up in Virginia in the 1600s, and have found references to them back to 1619 in some cases.
2) If your local library has access to Heritage Quest, one of its databases has local history books with more than 7 million digitized page images from over 26,000 family histories, local histories, and other books. Search for the county names, or variations of the surname (note that I have seen some "Loughmans" pronounce the surname "Lockman", so that might also be a possible spelling to search. Search this database for Henrico county, Charles county, etc. and scan through the books, or look at the indexes. If you don't have access to Heritage Quest, search Google Books for the County names.
3) If you are a direct descendant of Daniel's father James, check to see if there is a DNA group for likely surnames. If there is have your Y DNA analyzed so it can be compared to possible US descendants of Daniel.
Regards,
Nick