Helping two individuals to train for their first Marathon this year. Both will most likely be in the 3:30 to 3:50 range, so I imagine my experience (sub3) don't necessarily apply to their training, too.
My main concern is the long run. I'd usually max out around 20-21mi (2:30-2:45h range). I don't think it is a great idea to let them run the same amount of mileage but if I let them max out at 2:30h, they'll only get ~15mi in.
Also, they're not high mileage guys so the long run would already be >30% of weekly mileage...
Any tips?