thinning a SpatialPolygonsDataFrame

The Guerry package contains two maps of france (gfrance, gfrance85) 
which are quite detailed and large in size (~900K).
In writing a vignette for the package, there are quite a few figures 
that use the map multiple times in a layout, and
consequently result in huge file sizes for the .PDF files created.  For 
these purposes, the map need not be nearly
so detailed.

I'm wondering if there is a facility to "thin" the map by drawing it at 
a lower density of lines in the polygon regions.
When I was working with SAS, there was a GREDUCE procedure that did this 
nicely.

thanks,
-Michael

Michael Friendly     Email: friendly AT yorku DOT ca 
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT  M3J 1P3 CANADA