The practice area I would suggest is up river from the overhead power lines that cross Pea Patch Island, to Newcastle and the main channel Green buoy just off Newcastle.
If you have less than 50ft mast height pass under the power lines between tower 3 & 4 (counting from DE side 1 is on land, 2 is in water 3 next 4 is close to the submerged bulkhead, 5 is on green side of main shipping channel, 6 is on red side of channel, 7 is on NJ).
Water depth under power line is 15ft + then water all the way to Newcastle is 20ft+ to 9ft+ with shallow water on the DE side.
A good place to practice with chart, depth sounder and compass, many reference structures; radio towers, water tanks, bulkhead lights and features in Newcastle for charting using a compass. Space for tacking and features to practice holding a course on a bearing.