Planning a driving trip in Hokkaido

I'm going to go to Hokkaido, and after a few times travelling there and using public transport, I wanted to try a self driving tour around the area. I've done planning before by myself and it took forever, and I was wondering if there was any services out there that might be able to help with my planning. I'll be going in Winter/Spring time depending on my holidays from work. If anyone could link me a few good sites that would be awesome!
Thanks in advance!

Hi! I am also planning a six day driving tour skirting around the largest cities in Hokkaido. Here are some things I had to consider when I was doing my trip planning:

1. Cities and towns are few and far between so gas stations are also not as common as in other populated areas. I literally had to go on Google Maps and find out where all the gas stations are.

2. There are numerous rest stops around Hokkaido. Also called Michi-no-Eki, they are all over the place. Many of them are large and include free wifi, washrooms, restaurants, souvenir shops, sitting areas, and some even have gardens. Free parking of course. Please have a look at the website: http://www.hokkaido-michinoeki.jp/en/

3. I will not be utilizing the toll highway to save money, but you might. When you rent a car, be sure you include a transponder. Also, check out this website for more info: https://www.driveplaza.com/trip/drawari/hokkaido_expass/en.html

4. I have downloaded a few pamphlets for information.

5. It appears most roads (except the expressways) have a maximum speed limit of 50 or 60. That is SLOW by North American standards.

Further to the reply above have a look at the driving guide for Hokkaido

https://en.visit-hokkaido.jp/library/brochures/pdf/driving_en.pdf