Next stop was Nesodden. I have never been to Nesodden before. It is absolutely worth a trip. I parked at Alværn skole and walked along the forest road to To gård (1.5km). Following advice here, I walked nearly the whole way to the farm before following a signposted path to Tomåsen, but this took me in completely the wrong way and I walked quite far before I realised this. So I ended up heading cross-country towards the tower. If you are coming from Alværn, walk up the big hill and then just as you start going down, where the electricity cables cross the path to the left hand side, there is an unmarked path that will take you near the top.
The walk is about 2 km each way. Nice on a sunny day like today.