Look up Herb Elliot training. Sweet, simple and straight to the point with no non-sense.
Main things to do to build strength are hill reps (or sand dunes if possible), low reps i.e. 5 x 5 using compound lifts like squats and deadlifts.
Also important when you lift is to do a bit of every body group. Do not isolate like a bodybuilder. So do some upper body, lower body and some core and stability. Also do not do more than 2 to 3 working sets.
Working vs warm up sets
When you lift, for example squats. You should do 2 to 3 warm up sets followed by 2 to 3 working sets.
A good full body workout:
Barbell parallel squat 2 x 10 + 2 x 5
Lunges or box step up 2 x 10 to 15 per leg
Back extensions 3 x 10
Push ups 2 to 3 sets to failure
Pull ups 2 to 3 sets to failure
And some core and stability exercises
On your mileage kick it up to at least 100 kilometres per week, up to 160+kilometres in the winter during the base phase.
Typical week during the winter
Sun am 1.5 to 2 hours steady pm light jog + weights
Mon am jog easy pm 8 to 12 + strides and drills
Tues am easy jog pm 8 to 12
Wen am easy jog pm some sort of longer intervals or a tempo run + weights
Thurs same as tues
Fri am easy jog pm fartlek or hill reps + strides and drills + weights
Sat off or easy double
Also add some cross training if you want to replace some of the easy jogs with swimming or cycling.