Fowlers were a prolific lot on all reports but it would appear that your Fowlers may have migrated well back especially as America welcomed emigrants many years before Australia.
Frankly our successhas rested on finding when paeople emigrated and on meeting people with common ancestors on Genes Reunited.
Re Dorwards they were so prolific that they put Fowlers to shame.The Dorwards appear to have come from The area of Dundee north of the Tay Estuary.It's origins are set out in "surnamedb" and are said to be in Scotland that the office of door-ward to the King was a very honourable one and was hereditary.We have two people in the UK who we met through Genes Reunioted who are direct descendants of Dorwards.One said he has visited the area a few times and only had to say he was a Dorward and doors opened. Try googling "Dorward House".
The facts I outlined before for my wife's family are supported by actual registered documents, RootsUK plus IGI transcriptions, names handed down and family history.
The only knowledge we have of Fowler joining Dorward is the marriage of Amelia Dorward and Christopher Fowler on 17/11/1856 registered Sunderland.Obviously the connection for you comes much earlier.It is possible that one of Amelia's brothers did have descendants in America but that would be too late for you. It is possible that earlier brothers (or sisters) of these Fowlers did go to America but it could be from limbs of Fowlers way back.See the origins of the name Fowlerin "surnamebd".Mostly English and relates to collector of birds etc - are some claims to be of ancient ANglo-SAxon (German) origin as well.
Dorwards also appear to be seamen/mariners- The Firth of Tay and Dundee was a real sea port.
I really can't get further back than the 1789 marriage of Jonathon and Margaret Bird at Catterick and the fact that the family moved from Catterick to Durham County between 1794 and 1798 no doubt for the developing opportunities in mining.
I din't has access to immigartion to the USas I am not member of Ancestry.com.
I can say that we know some other family members did go to Canada but that is around 1900 anyway.
We did look at a site that showed the spread of Fowler names in the US and it was phenomenal.I guess it has had many more years to develop.