May I correct something about Ascension. It is open to limited numbers of visitors and is served by RAF flights though these are usually chartered civil aircraft such as the A330-200. They may of course be RAF fleet too, again the A330-200 springs to mind. If you are fit, not limited by medication, have the proper travel insurance and the vital permit from His Honour the Administrator [also the Magistrate and Receiver of Wrecks] then please go and enjoy this unique island.
You just have to get the necessary papers and permits and be organised but ASI is open. Google it for details.