I want to correct myself here – supercache was not really working, I just thought it was.
DH has some documentation on it here:
https://wiki.dreamhost.com/Fine_Tuning_Your_WordPress_Install
They suggest turning the plugin “Half On.” This is really just using wp-cache, and in the same documentation it points out that wp-cache is not recommended! Sure enough, trying this, my server immediately served up a 500 error.
So I deactivated supercache and installed hypercache instead, and that is working.
https://www.satollo.com/english/wordpress/hyper-cache
I never tried your tip, forefront, but hypercache is working fine for me so I will probably leave it that way.