I agree with paul187 about the 115 pop. Getting to 115 pop is the primary goal in classical (unless you are doing a FH, which would be suicide with Greek against Norse because without troops he will easily kill you before you get there). You need the troops in order to prevent your base from simply being overrun by a pop limit army before you reach heroic. Your defensive buildings won't do if he attacks with maximum troops and you only have troops for half of your maximum pop limit.
True is that 115 pop can be reached quickly by building hippikons. Wrong is that the longer build time of hippikons is of much importance, because if you produce more resources than your stables can convert into hippikons, you can just add another stable. The 75 wood (Poseidon price) for the stable is quite low and not a factor at all compared with your other expenses (a single hippikon costs way more than that). Norse longhouses cost 110 wood each, so you can easily build four stables for their usual three longhouses and still have paid less wood. Using only one villager per stable will minimize villager second consumption for building construction and still get you there sufficiently quickly.
The downside is that he will reach pop limit much earlier than you hit heroic age. He can then attack your gold miners and/or woodies. On some maps there is no wood close enough to your home base so that your woodies would be protected by your towers. On most other maps, there is only one such wood, which the Freyja Norse will burn down. As the consequence, you have to cut wood in an area that is not covered by your defensive buildings. The hippikons you have are too weak to do the job once the Norse has got to pop limit. So he is superior to you at the place where you are cutting wood, which is a very bad thing.
Often enough, you'll also want to mine gold at another mine, because your home mine will hardly suffice for getting both hippikon pop limit and heroic age, so you have another place in the open field where you can be attacked by superior troops against which your hippikons will lose. You will also have difficulties moving your hippikons from one vulnerable spot to another in time, because his RC are just faster.
You can mount an articifial defense at those gathering spots by building towers there. But that costs you 200w/100g for the tower upgrade and another 200w/100g for every tower you erect. If you want these to be really effective against his RC, you will also have to spent 150w/150f on crennelations. Without crennelations, one or two towers will not make much of a difference against his RC in a pop limit armies battle.
On top of that, you have to pay 200f/100g for the obligatory medium cavalry. He still has thundering hooves in addition, enlarging his speed advantage and greatly increasing his hitpoints. You can counter by paying another huge load of food for spirited charge, but still the attack advantage you get will not compensate for his hp bonus. Actually, you need Thracian Horses to get the same bonus, which will require heroic age, be more expensive than thundering hooves, and will not give you the speed improvement that the Norse gets on top of the hp bonus.
With all those secondary costs, plus the resources you need to produce pop limit hippikons, you are nowhere near getting to heroic age quickly. Your hippikons do not do against his "raiders" even if they are in position to defend your villagers when the RC attack (unless you have buildings positioned wisely to create narrow spaces, in which hippikons fight better than RC because they are stronger per unit). And that is the problem.