First, I don't think so. Second, an over-rated subsidy is still a subsidy. So even if they are over-rated, that's still no proof of VLM's statement -- it's more just looking the gift horse in the mouth.
> We have energy coops (which we pay for entirely)
This isn't true everywhere.
> we have a road system (the most expensive parts used by everybody)
Perhaps for the interstate system you could make this case. I'm not sure. Certainly there are cases where the interstate system inconvenience cities for the benefit of an extremely tiny but politically powerful rural district. The same happens with state highways.
But at the state level, rural roads are heavily subsidized. State highways are typically extremely important to rural areas, and those are mostly funded by urban and suburban tax bases.
> but only a tiny fraction of rural residents are in farming
But farming is still very important to local economies in rural areas, even if it's no longer a major employer. Also, "some" is a bit of an understatement -- half a trillion in federal funds over half a decade. And that's just the main farm bill -- excluding other federal and state assistance programs.
> What else?
* Schools for sure. Most states heavily subsidize rural schools in their funding formulas. States and the federal gov't also subsidize rural schools through programs that are not even accounted for by these funding formulas -- e.g. tuition waivers and sometimes even salaries for teachers that teach in rural schools.
* Federal and state entitlement programs -- this one isn't even close to debatable.
* Political representation. Again, not even close to debatable. I consider this independently of all of the other indirect economic benefits that stem from the representation for a lot of reasons. To give one, the conservative social agenda disproportionately targets and complicates the lives of the non-white non-christians concentrated within cities.