I am doing a fairly extensive analysis of Maryland archive records to help answer that question. The easiest answer appears to be that 1) he was brought over to become part of the landed gentry, 2) he served as Capt of Rangers for which he was well paid "by the powers that be" in the State, 3) he married the daughter of a wealthy widow 4) he was able to live "off of" his family and friends while he accumulated his own holdings. 5) his holding were several, but, not terribly large - a few hundred acres, at most - not thousands, like the "insiders" had 6) he cultivated powerful friends who allowed him some leeway in building some land ownership. More details and support will be written up over the next couple of months. Send me a note at firstname.lastname@example.org and I can share, as it becomes available in readable form.