I'm looking for a cable release for my D3100 so this only speaks to your concern about vibration.
You can also use what is called the "hat trick" to minimize vibrations on long exposures. Cover the lens with a hat or other object to block the light (hold it there and do not let it touch the camera) and open the shutter. Let it settle down, move the hat and begin timing the exposure. When done, block the light with the hat and close the shutter.
If you are being this careful consider that you also need a very steady tripod:
Use bungi cords to pull it toward the ground
Do not move while the exposure is taking place
If you must move, step softly and get 20 to 30 feet away away from the camera.
For those that are really serious about vibration and will work from a fixed location consider a 4' deep concrete pier isolated from the soil the top 2 feet with 4 inches of packing p-nuts. Fill the bottom 2 feet and use coffee cans or PVC Pipe to make a form for the top 2 feet. Worked for my telescope.
Jan 3, 2014 by
Favorite Subject: Nature
Nikon Family: 2-5 years
Role: Serious passion, hobbyist