If it's your opinion it's your opinion. I don't think that 'wanting more power over more things' is something inherent to socialism. All governments take power over things when they think it's necessary. A particularly controversial example would be abortion restrictions. That is an extreme intrusion by a government into the literal organs of its citizens but to a religious capitalist it makes sense. Need more workers and more consumers after all.
I don't see that there's any meaningful difference between an interest free loan and a subsidy. Say the farmers don't pay up and ask for another loan, are you gonna starve on principle?
Lots is wrong with dirt roads, they're just inefficient. So much money and resource spent on fixing and maintaining vehicle suspensions and the extra time needed to go slowly which is all unnecessary with a proper road. I love trains but they can't do everything, we're not running tracks to every home in order for the mail train to come deliver your package etc.

As for private parties, this is also just the least efficient way to do things. Roads need to be compatible with each other, have the same spacings the same areas for communal services like electricity water and gas and so on. Who's gonna enforce all that with no profit motive? It would have to be a government entity, at which point the government might as well just build the roads in the first place and charge everyone a general usage fee, but since it's a government this is called 'Road tax' and is already implemented in most European countries. This isn't even socialism it's just the basics of what governments are for: taking care of 'societal chores'.