So I’ve got aspirations to do Edale Skyline next March

I’m planning to do one of the Dark and White mini mountain marathons in Sept, Windgather in Oct and the Roaches in Nov. (After that it would be gravy pud and lambs longer leg.)
If I then did at least one long run a month of ~ 15 miles and 4000 ft, plus weekly short runs of 5- 8 miles would it be enough to get me round the skyline? Or am I seriously deluding myself and the level of training.

As an indication of my ability/inability my furthest run to date was Kentmere in just under 2.5hrs!