Depending on what kind of roades you prefer, there are lots of good routes to the meeting. If you prefer a quick route with good road standard, take the main roads to the city Kongsvinger in Hedmark, app. 100 kilometer norteast of Oslo.
If you are coming from or through Germany, the easiest way to Kongsvinger is to take the ferry from Kiel (D) to Oslo. Then drive the E6 towards Trondheim. At Kløfta, take to the right towards Kongsvinger, road 20. You can also tak the ferry from Kiel (D) to Gothenburg (S) and drive by Trollhattan, Vänersborg, Säffle, Arvika and Kongsvinger. The ferry to Gothenburg is probably cheaper than the ferry to Oslo. Antoher route is to drive to Puttgarten (D) and take the ferry to Rødby (DK). Then drive to Helsingoer and take the ferry to Helsingborg (S). The distance from Helsingborg to the meeting is app. 600 kilometer, from Gothenborg app. 320 kilometer.
From England you can take the ferry from Newcastle to Bergen (N) or Gotheborg (S). From Bergen there are several breathtaking roads from west to east in Norway. Road 7 over Hardangervidda is very nice. Also road 55 over Sognefjellet is a good GS road. Road 50, Hemsedal is nice. Road E16 is OK to Leira south of Fagernes. After that, drive road 33 to Gjøvik / Minnesund and road 177 to Vormsund. Then road 20 to Kongsvinger.
From Kongsvinger, drive road 20 direction Elverum. Then take a right into road 200 direction Austmarka / Torsby (S). After app. 20 kilometer, this road ends up in a crossing. Tak a left direction Torsby (S). There is a road sign that says “Dragonmoen Camping” to the left. After app. 4 kilometer another road sign says “Dragonmoen Camping” to tre right. From the second sign to the meeting it’s app. 1 kilometer gravel road.
Be aware of the speed limits in Norway. The fine is very high, and you can easily loose your drivers licence.