What do you care about more 10k or marathon?
In either case, I would make the weekend count. Long runs, with longer up tempo stretches at half marathon to marathon goal pace, at the end.
I like workouts like the following:
45 - 60 min at usual long run pace, followed by 3 x 2 miles at MP or HMP.
45 - 60 min followed by 1 mile, 2 mile, 3 mile @ MP/HMP.
90 min, followed by 5miles @ MP.
After a good warmup, 20 min or so, alternate hard / easy efforts at your target paces.
60 min run, some local race 5 miles, 10k, etc at MP/HMP long cooldown after.
My philosophy is to become accustomed to running at your goal pace, when you are fatigued. Everyone can look like a hero in the first half of a marathon, half marathon, but the real work/effort comes in the last half.
Don't tell me how many miles you ran last week, tell me how many miles you ran at your goal pace.