Adrian's advice is good as always. I'd just say, make sure you do the lifting on the non-cycling days, it's a bit much for your body otherwise.
The 20km cycle will make bulking up harder (burns through a lot of fuel), though the cardio fitness will make your workouts a lot easier, in that you won't have to rest as long between sets.
As a tall guy and someone cycling 20km every second day, you'll need to eat a lot to bulk up. If you are ever hungry, you are not eating enough. Pasta, rice, potatoes, chicken, tuna, nuts, beans, lots of fresh fruit and vegies...