If RCM data is not available for your region or is still too coarse, you can use Statistical downscaling. A whole range of statistical downscaling methods have been developed. Essential for doing a statistical downscaling is the availability of local climatological data. The results of the statistical downscaling become better with higher quality and longer duration of historic observed weather data. If you have good data for a particular weather station (or a range of stations) you can downscale the climate model to that particular station. If you have a good gridded data set you can downscale to that grid.
For Statistical downscaling, a statistical relationship is developed between the historic observed climate data and the output of the climate model for the same historical period. The relationship is used to develop the future climate data. Statistical downscaling can be combined with bias correction, and is sometimes perform in one single step.