I love my BlueSeventy booties. They help some with the cold and they make it much more comfortable running to the transition area. Mine come off very easily and quickly. Put them on first and then put on the wetsuit.

I'm also a big fan of the neoprene hood for cold water swimming.

If you have the chance, before the gun goes off for your wave, start splashing the water on your face to start getting it used to the shock.

I tried my wetsuit over a long sleeve Under Armour compression top; it was a little hard to get the sleeves on but not too bad (my wetsuit sleeves are pretty tight). The suit came off easily. If the air temp is cool you can then just start riding with the top on.