You could try a ligther desktop instead xfce, as openbox or similar. Disable all innecesary memory usage (like virtual desktops, virtual terminals, applets, services you dont use, etc). The apps in 5.8 std are ligth enough, but I think you will have troubles with web browsing. Almost every browser but dillo are heavy. Dillo have some lack of features. You can use dillo for general browsing and move to another if a site doesnt render properly.
Hope this help, let us know how is going, I really like to know about how can vec run in minimal hardware.