With a 4+ hour drive, it's gonna be hard to motivate people to get down there . . . BUT, if you can build you local scene up a bit by throwing regular smaller tournaments, someoday maybe you could throw a *major* and get people from Eugene to come down and maybe even a few portlanders.
The guys in Eugene did a good job of this last summer. Had a few smaller things after they opened and garnered local interest. Then they threw a HERB style major and got people to come in from out of town - you could follow their lead.
viewtopic.php?f=9&t=1233HERB Style is the format for Rose City Showdown NW Oh-pin and NW Pinball Championships. Basically what Dropshot described up above only you can keep buying entries. If you think you want to do something like it someday, I would strongly suggest coming up for Showdown - even if it's just on Saturday to see how it works.
First things first though - cut your chops on some local stuff - Head to head is very easy - who cares if you draw Comet????? Both players have to play the same machine . . . Or better yet - only use 3 or 4 of your best working machines when you're drawing matches. You don't need 12 machines for a 15 person head to head tournamnet. 4 is PLENTY - we have 30 person tournaments on 4 machines all the time.
Oh and I wanna play some SPECIAL FORCE!!!