Yep agree, you'll need more than 2-3 weeks to make it anything like worthwhile, it's a long way!
You say Netherlands and Germany, what after that? there is a big stretch of water, Ferries? if you drive into Denmark you then have the option of bridges to Sweden and drive up or ferry direct to Norway, many choices of ports.
If you choose the bridge option the tolls are slightly less than the ferry costs but a lot more driving.
A lot of roads in Norway are toll.
Have you thought what you actually want from your Norwegian trip, a lot of the outstanding scenery is middle to top of the country.
Tell us a bit more about what you want from the trip for more in depth info.