Civil records are held by the county and state in all states but 6. Those 6 are the New England states. In New England, the civil records are held by the city or town and the state. Some years ago, the city and town charged less than the state for records, I'm not sure if that is still the case.
Restrictions vary from state to state on availability of records especially to non-relatives. You might need him to do the requests and he might need proof of descent. I've never worked with Virginia records.
The site stevemorse.org might help you in searching Ellis Island and census records if you have trouble finding them. You will need a few minutes patience to learn how his site works. It is especially helpful with Ellis Island, and I have used his Census finder to locate addresses on various censuses when I can't find the person.
Ancestry.com US has a lot of city directories. I don't know how many the UK put out, but every city in the US seems to have had city directories in the past. - Listings year by year - arranged alphabetically by surname, giving their address. Good for locating relatives also, if they are living at the same address or very close by. Some city directories include a cross-reference by street address.
There are city directories on other sites as well.
Biographical histories by county were popular in the late 1800's. You might find an ancestor in one, if so it often gives his parents, children, religion, sometimes origin in Europe, etc. Google for 'biographical history of --- county' or somesuch to find them. Also some counties have good rootsweb or genweb sites that tell you what resources are available.
Local librarians have been very helpful to me as well. They usually will make photocopies of newspaper articles if you can give them a date. Good for looking for death notices and obituaries. They have never asked if I was related, though I usually tell them if I am.
An obvious one: findagrave.com. I don't know how much coverage they have in the UK, but lots of coverage in the US. Catholic cemeteries some, but not as much as others.
Boundaries changed often, if the ancestor seems to have moved from census to census, it might just be that a new township, borough, county, etc., was formed or changed boundaries. Write down every place mentioned at the top of a census form, Post Office included. It will help you find them on a map to keep things straight. And you can usually find an old map of any area you are interested in.
And Virginia is incorporated funny, but I forget how. I think all the cities are stand alone counties or something like that. You might need to learn about it, I don't know.