In reply to Removed Usersebastian74:
> Dear All,
> Currently I tend to run 3 times a week, getting 25/30 miles a week, due to work/family arrangements I would find difficult to run more, maybe 35 miles;
What kind of terrain are your training miles run on? 30 miles a week on hilly trails is quite a bit and will put you in a better place than the equivalent on the road.
FWIW, my first full trail marathon was Greensand, which was about 1000m of elevation so a similar profile to what you're talking.
http://www.trionium.com/greensand/
I managed it in under 4 hours without an epic amount of training. Looking back on Strava though at my heart rate analysis it was ugly, but I remember enjoying it (it was a beautiful day).
The great thing about trails marathons, is obviously you lose a lot of time going up hill but if you really fly downhill it can help mitigate the problem.
Anyway, so if you can't run more distance (and you will need a long run every couple of weeks, and that can easily be half your weekly mileage in one run) then concentrate on quality. Get out on the trails as much as you can, practice hills and descending.
Good luck