If your niece is based at one of the air bases in the East of England e.g. Alconbury, Mildenhall etc there are some interesting places to stay and see in East Anglia. The Bull at Long Melford, The Swan at Lavenham ( Lots of Aif Force WW II memorabilia) Le Talbooth at Dedham. The area around Dedham is a very pretty area. It was the area that John Constable the landscape painter painted a lot of his works. Nothing is cheap over there. If you’re doing any traveling outside London and are hiring a car, specify that you want a diesel. Gas is horrendously expensive over there and the diesel cars get far better mileage.
My wife lived for years in Elmswell, near Bury St. Edmunds. Her son works in Lavenham. She’ll be over there next week. It’s a nice area to live.
https://militarybases.com/overseas/united-kingdom/
It is showing only 5 bases operated by the US Air Force (and listed as RAF). 4 are in East Anglia, which is the least spoiled area in England. Still has picturesque stone & thatched cottages, farmland and historic buildings.
Worth a trip....even though the English drive on the left.