Start working on that sit command when your cav is not so excited eg while you are watching TV; during the ad breaks call him over, tell him to sit and quickly give him a small piece of something great like hard cheese, bacon rind etc. make it a game -- every time he gets up tell him sit and quickly reward him -- your aim is to make sit so wonderful that eventually he will do it even when he is excited. I would suggest you don't place him in position -- just use your voice and holding the food just over his head-- not high or he will jump for it-- also don't waste time telling him No -- tell him what you do want him to do. Get everyone in the family involved -- get them to walk him up the hallway sitting every few steps using an excited voice and a food treat EVERY time. As far as jumping outside, prevention is a great weapon -- have him on a lead so he can't run near the car, and continue to tell him sit as a game every few steps as you walk over to the car --don't open the car door until he is sitting quietly. Make sure you tell him how wonderful he is for playing this game and eventually you will be able to fade the food rewards and only use them occasionally. Two excellent web sites are dogstardaily.com and dogmantics.com/free-video-list/