If you get the RJ you will do ground training on all 3 variants during initial training, and there's a good chance your initial training in the aircraft will be spent in the 700 if not in both 700 and 200. Your training will be in whatever airplane your check airman happens to be flying that day/week and a lot of them bid for the 700. I wouldn't plan on holding DEN right away though. The most junior FO in DEN right now was hired in March '07. most new hires get chicago with some going to milwaukee. There's currently a long list of ORD based F/O's waiting to go to DEN.