Gerilyn, while I am not a rental agent, I may suggest checking out http://www.DistinctiveFlats.com.
They are a boutique rental firm based in Wash Park however they represent units in the Cheeseman Park area as well as Capitol Hill and points east and south.
I would also suggest checking out RedPeak Properties and Cornerstone (sorry I do not have their web addresses off-hand). Both are mid-size management companies with buildings and individual units in the area you are searching.
Finally I have saying this but sometimes driving around the area is an option as there are properties that are managed by the homeowner or an on-site resident and thus are not in the active marketplace per se. Unfortunately Denver rental market does not have a robust multilist service for rentals making rentals harder to find. Also we are at historcially low rental inventory which adds to the challanges.
I hope the above helps somewhat. If I were a rental agent I would be on the phone immediately unfortunately I am on the sales side however the above companies may be able to assist as I have worked with them on various client related desires. Good luck....