Four different age divisions have taken center stage at the inaugural Golfweek Pacific Northwest Senior Championship. Over the entire field of elite amateurs, it is one man who leads them all. Craig Larson carded a 2-under 70 at Wine Valley Golf Club in Walla Walla, Washington, on Tuesday. The Lakewood, Washington, native is making the most of his near five-hour trek so far. After a tumultuous opening nine that saw just two pars on the scorecard, Larson settled in nicely on the back nine. With three birdies on Nos. 10, 15 and 18, he was able to erase a front-nine…