To be honest you'll be surprised just how far away it is from Sapporo. To take the JR Sapporo Rapid Airport Express takes just under 40 mins - which is the best way of getting into the city - and costs just over 1,000 yen. If you're taking a car then there's essentially two options
If you're hiring a car, the quickest way is the Sasson Expressway, however, this is a tolled road, so my suggestion is just take the normal roads in (takes only 10-15 mins longer).
Non-toll road (43 km - 1hr 11mins)
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