Morning Everyone, back in the land of sunshine and more importantly internet access!
Minni: Reading what you have been posting I think that you have already decided that you need to put in more work at a higher pace than you have done in the past, for what its worth I agree completely! Based on my own experience it was only when I started including tempo runs of about 6 -8 miles at 1/2M pace plus speedwork sessions each week that I finally cracked the 3-30 barrier.
If there are no 10K races around your area then time trials with club mates could be a good substitute, I believe that racing 10K's teaches you to run at a pace and maintain that pace. Speed work is also good for this, if you want to run 8 min / miles consistently for 26 miles you need to know exactly what that pace feels like and be able to hit it without the aid of a garmin or anything else. Of course its also necessary to build in sufficient recovery runs as well into your weekly schedule.
As to running your LSR off road on a hilly routes, why not? I do most of my long runs on undulating sand and gravel tracks, hills are your friend! The splits you posted for your most recent marathon show that you slowed towards the end therefore running at race pace for the last section of your long runs will help to teach you how to maintain pace on tired legs.
I will dig out my copy of P & D tonight and see where you are at, but it seems that your manging to keep to the schedule OK, as someone posted above schedules are written for a reason and this is the base building stage so there is no need to get obsessed about speed yet but also there is a need to keep some speed work in there. For example back in August when I started training for Athens marathon and then Dubai I was running my tempo runs at 4-40 min/K's and my speed work was 6 x 800M at 4-20 min/K off 2 minute recoveries where as now with three weeks to Dubai tempo runs are around 4-20 Min/K and and I tend to do 8 x 1K at 4-00 min/k off 75 second recoveries, progression!