I've done quite a few funerals. The telephoto will be great. Also have a wide to get the shots at the cemetery, i.e, crowd, in military salutes. Ask someone in the family beforehand do they want is shots of the casket. I imagine it will be draped. I've even photographed the body (not as rare as you would think). Practice being able to slow move to different positions without being noticed. Usually during the time of the eulogy, im set up in one spot in the back with my telephoto. Get a program if there is one, so you'll know what's going on and at what point in the service. Actually, its not too much more different that doing a wedding, other than its sad, and you really try to not be seen.