Guide services are a good way to go. RMI is one of em, but I would recommend one of the others. Especially, if you can go up the Emmons route. Solo climbing is a no go without permission from the climbing rangers and I can tell you that you won't get permission. Going with experienced friends is the best way to go. Start conditioning now. Lots of cardio. Mt. Adams, the South Spur route is a good non technical (no crevasses) climb. You will hear people say that Rainier is a long walk up and it is not very technical. Some routes can be. Then again, those same routes can turn to bad ju-ju due to weather, avalanche conditions, route conditions. YOU DON"T WANT TO SCREW AROUND ON RAINIER!! Trust me, I have lost friends on Rainier and have spent A LOT of time there. Check out The Mt. Rainier Climbing Guide (may not be the correct title) by Mike Gauthier. He is the lead climbing ranger up there and knows the mountian. His website has some good info www.mountrainierclimbing.blogspot.com. Another good book just about general Rainier stuff is, The Measure of a Mountain, by Bruce Barcott. Feel free to send me a message if you want more info.