Deer Lake Tr starts right at the paved lot of Deer Lake, goes around the south side of the lake, past some really cool camp sites and takes a left to the west up the ridge. At the top you can go left, south, to packer saddle, straight and down which connects directly to the top of baby heads, or right to Little Deer Lake and Snake Lake Tr.
You can drive all the way through to A-Tree and Plumas-Eureka SP.
I've actually never been to Snake Lake, but I've been down the road from the top until it started to get technical. We were alone and in my stocker, so not taking any chances. The same day we got into and out of some trouble going down the Little Deer Lake Tr due to snow. Always remember that down is easier than up.
Great map here:
© Sierra Outdoor Recreation Maps