...make buildings on a large city map?

[lisze]

I am currently stuck on my city Durndl. I would like to add buildings to the map.

Map Dimension: 3520x3520
Map Scale: 3 feet/pixel (any smaller and my map size was too large)
Programs Used: Gimp, and recently Inkscape (I'm still learning the latter as I only d/l'd it last week); I am willing to d/l and learn another program, providing it is free.
Limitations: I work on a laptop with a touchpad. I do not have a regular mouse or tablet. Also, the graphics programs work slowly on this map (gimp is better, but some things still take time and a prayer that the program won't freeze and shut off). I'm getting more RAM soon, but even so.

City Population: 80,100 people
Time period: A lot is based on 15th century Florence, but I steal from other time periods as it seems appropriate.

Goal: I'd like to make buildings to fill each of the blank spaces between the streets.

What I've tried: Creating a large page with shapes on it in Inkscape and then slipping that into a layer on Gimp; Using that large page to create a pattern on Gimp and using pattern fill; By hand on Inkscape using paths (very time consuming for a result that did not appeal, even as a base).


The colored sections are the wards, once an arbitrary division by the city police, but now governmental entities within the city.