Originally Posted by
canabiz
Is it possible to pick up the rental car in Sapporo and return it at Hakodate, with the same agency of course, possibly with a fee?
Sure you can. Quick look up for month of August, picking up a car at Sapporo’s Chitose airport and returning at Hakodate airport. Mid-size rental from Toyota Rental Car (one of major in Japan) for 8 days come out as 8303 yen/day (US$75.67/day).
Only thing I will mention is that during August will be peak of summer vacation. If your travel date will coincide with Obon period, the busiest time of summer vacation period in Japan, then everything will be very busy.
You should put cushion on your plan. Especially during Obon period even roads can be slow going, take longer time to get to destinations. Then parking can be time consuming. Expect lines at tourist areas you are planning to visit.
Add waiting time for places you are expecting to visit. If your travel plan coincides with Obon period then add driving time, roads probably will be slow moving. Obon period for 2016 is Aug. 13 – 17.