I am going to be in LA the last week in April and have a week between that meeting and one in Omaha. As a history nut, I have been looking for a way to visit some of the key spots along the trail of exploration of Lewis & Clark. My initial thoughts are to fly to Portland, OR on the 29th, take a bus (?) to Ashland, and then head east from there. Any suggestions for Oregon, Idaho, Montana, the Dakotas, etc. would be much appreciated.