Many who have not done them before will find the wall sits to be very straining on the quad muscles, and you may get a lot of pain from the soreness (at least I did). Using a large ball (like a 24") between your back and the wall at first will help to "get into" this exercise, reducing the friction.
Otherwise it is very good at building the quads. A great exercise for a motel when traveling.
Also, with the calf raises, you can hold a 20 pound dumbell or a gallon jug of water in each hand - or we take the large physical therapy type of elastic bands (Therabands) when we travel. Put one side under your foot and the other in your hand for more resistance.
We have a whole series of "traveling" exercises using the Therabands and an inflatable ball which utilize such things as doors, door handles and your body. They work quite well. I have some pics if anyone is interested.