HSR is most efficicent for mid range trips that are 200-300 miles long. Anything shorter, might as well take a car. Anything longer, might as well just fly. That is the main reason I that the eastern corridor is being built up first. Trips between boston/nyc, nyc/philly, nyc/dc would all be hugely popular.
As far as taking land, because of eminent domain and The Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970, the US can take property at fair market value. It isn't just hey this is ours now here is a check. The program actually does a lot to help people relocate and even affords them extra money for relocation expense alone.