The golf ball retriever is a great tool for this purpose! We have one the extends out about 30' which when we remember to take it, has always done the job. You ask where to grab the boat. I'd say it depends on the situation, but generally all a sailboat needs to get free is just a little lift, or push, so we typically try to lift near the center of the hull, or push on the side of the hull. If you can hook the keel, that is not bad either. The rudder is not the best place to push, as it is more likely to be damaged.
The only times that rescue has been needed, was when we got the keel fouled on the "smang" which is always the worst close to shore, as the water is shallower there, and the sunlight gets threw to the "smang" and like the "Swamp thing" in that old movie it grows stronger.
I can see the same stuff near the shoreline in the photo you posted. When it gets really bad here, we use a heavy steel rake with a line attached to it, to dredge the shoreline. Pretty simple, we just throw the rake out as far as we can, and pull it in slowly as it rakes the bottom. We put the gathered "smang" in a pile and let it dry (it's to heavy to move when it is wet) then we take it to the dump.
It is really an interesting form of plant life. It is very strong and fibrous. The good news is that most of the time, the wind is on our side, so we can work the boat free by rudder and sail manipulation. If that fails, we use the golf ball retriever, or drop in a rescue boat to help push the boat free. I have been in "irons" (dead calm)a few times, and had to wait a little while for a breeze to get my boat back to shore.
Your pond looks manageable, just stay away from the fountain. We have a lake with a fountain that is held in place by 2 ropes from the shore, one on each side, which if not submerged, will snag the keel, and if that happens and the wind is blowing the wrong way, it can push your boat into the fountain.
I have had that happened and all I can say is I was very lucky and escaped with no damages. I have attached a picture of what we now refer to as the "death fountain" and the areas where the ropes that hold the fountain in the center of the lake are the "devil's triangles".
Our fountain puts out a lot of water and will knock the boat down on it's side, I was lucky in that the wind kept blowing my boat into the center of the spray, once it was in past where the water was pounding on it, she righted herself, and with great helmsmen ship, I was able to sail her out of the "death fountain's" grip.
This was truly a memorable few minutes. From that time on, we got some slump stone blocks and used them to sink the lines deep enough to make a safe channel to use to get around the fountain. Not sure if the guys that maintain the lakes appreciated us doing it, but the darn fountain is a hazard to navigation, so we figured we had maritime law on our side, and figured we have the right to keep a channel open. Next, is channel markers!
Where ever you sail, prior to putting your boat in the water, a little information gathering can be very helpful and will enable to you steer clear of any shallows, or other kinds of avoidable hazards. The same would be true of going sailing in a full size boat.
Not to worry, sailboats are of the most sea worthy crafts on the water, and can take a lot. Enjoy, have fun.