Denver is a fantastic place for everyone! There are several great neighborhoods that are close to light rail and public transportation. If you want to see what different areas there are you can go to my website and click on "neighborhoods". I am thinking Central Denver would be good for you becuase of your $700/month budget. However, don't except too large of place. Moving out to the suburbs gives you more room. My website is http://www.wendyglazer.com
You may think twice before moving near Colfax or in the Capitol Hill or Uptown neighborhoods - although, the areas are more affordable. The best way, in my opinion, is to take a drive in the area you are considering at about 10 p.m. to see if you feel comfortable. Although, not so easy if you are in Baltimore. :) Denver has a large homeless population, most of which are fairly harmless, but sometimes individuals made me uneasy.
If you don't care about living in Denver, you may also check out the Denver Tech Center, which is at the South end of the Light Rail system. There seems to be something of a nightlife there. Plus, there are some terrific restaurants.
You may want to check out this map - http://www.spotcrime.com. It will show you where the crime is in Denver, or surrounding towns.
That said, Denver is a great place to live. Compared to Baltimore the crime is minimal, there's a lot to do outdoors and the population is generally young. Plus, it's sunny about 350 days a year, or something ridiculous like that. Good luck! Let me know if you have any questions - I'm happy to help!
The real answer is anywhere that you feel safe.As an agent I would take you to many different areas and show you places and it would be up to you to decide.I would help you in any way by getting you all the necessary reports that you would require about certain areas,but it is ultimately a feel that you would have.I would be glad to answer any other questions that you may have.Just come to my website and ask me a question.I am always available.