Lidar is good enough for planning purposes and is freely available from most states GIS data. Possibly, after getting a plan developed with Lidar data, you could do a more detailed ground survey where needed.
NH Lidar data:
https://granit.unh.edu/resourcelibra...ltopics/lidar/
You can view the data in this interactive online mapping tool:
https://granitview.unh.edu/html5view...er=granit_view
Dave