The pilot reported that 20 gallons of fuel was added on May 18 and stated this brought the main tanks up to near full (160 gal). Between that fueling and the accident, a total of 6.0 hours were recorded and an additional 80 gallons of fuel was added. Records at the accident site revealed that the fuel burn rate of the aircraft was 40 gal/hr (total). The pilot reported that he relied on the external wing site gauges and known fuel added for fuel information rather than the cockpit gauges which he considered unreliable. Additionally, the pilot preferred not to 'top off' the fuel system to keep the aircraft weight low. After departing for the 98 nm return trip to Seattle, the aircraft exhausted all fuel aboard approximately 8 nm short of destination. The pilot then executed a forced landing onto a divided residential street which was the only suitable terrain available. During the landing, the aircraft struck a light pole and vehicle. Post-accident investigation revealed that the aircraft was not refueled at Chelan, WA for the return trip.