P4 collision avoidance is not a solution to all problems, so don't rely on it.
Keep in mind that almost all of the lake is within 5 miles of many airports around the lake and therefore could be a 'no fly zone'.
Be sure to get the 'hover' app or the B4UFly app (or both) and check yourself before you take off, don't be "That guy" that ends up on WMUR or the national news.
Don't drop your drone in the lake, they don't like water.
Practice in an open area, away from trees, and don't get your back against anything like a fence, house, etc. You need to be able to get away if you screw up and have this thing heading towards your face.
Until you have a LOT of experience, be sure to have the 'front' / 'nose' / 'camera' pointed away from you always before taking off or landing. This is key to not getting screwed up where left/right front/back is reversed from what you expect.
Consider joining a local RC model aircraft flying club where you can get tips from people that have a lot of experience flying these things.
Good luck and have fun!