Your understanding of how the route affects the price is misguided.
It has nothing (or very very little) to do with how difficult the terrain is to navigate, it has everything to do with who owns the land, and how much they want to charge for it.
Often these "owners" only purchase the land once informed that it is a potential high speed rail route.
Having had a night to think on this...
It sounds like CA needs some eminent domain reform. I don't live there, so I don't know (and don't are to look up) the law. In the US in general the constitution requires a fair price, if someone bought land we have evidence of the fair price. My general advice (though often not allowed by law) is that you should pay 10% more than fair if they sell now, but if they go to court we only pay fair price (thus if you disagree with the fair price by 5% you should sell now anyway)
In a way, it’s a transfer of wealth from masses to these land owners (or brokers in a sense).
They will do the same to a different route. Once you buy land you become committed to a route. Reform is needed, but I'm not sure what.