Hi
Which month are you planning to go and where? Are you thinking of offroading/play sites/greenlaning or just enjoying the scenery and the country?
Area, possible offroading and the month will predict what kind of boots you want to wear. Offroading is mainly either strictly private or organised through clubs here I'm afraid.
We normally drive SUVs and trucks with spiked special, highly siped winter tyres like these ones
http://www.nokiantyres.no/ during winter, but in autumn you shouldn't need to be afraid of that for most areas. I live in Mid-Norway and have grown up in the southern parts, been around pretty much all of Norway and parts of Sweden and Finland due to outdoor activities mainly scuba-diving but also al lot of hiking, hunting and sailing so I'll be happy to give you some advice.
I would recommend the part coast from Aalesund and north, especially Lofoten and Vesteraalen. Mountain areas of Dovre and Hardangervidda. All these places are very nice to see by car. Southern parts of Norway, and west coast of Sweden is very nice, but different, and it does much better in summer and by boat. I would recommend cities like Stockholm, Bergen, Aalesund, Trondheim, Tromsø if you guys would are interested in coffee-drinking, people-watching and architecture apart from driving in mud.
BUT- it seems hard to get here by car. I haven't found any ferries between Norway or Sweden and England/Scotland. Those days seem to be gone

Erik