Hi Colin. With regards to buying cedar in NJ.....since I'm not in NJ, I can offer to suggestions as to where to buy blocks. But I can add that if at all possible, buy cedar cut in the winter. The sap content is lower and it will check less. Now, having said that, here in Vt, I can buy all the winter cut cedar I want, and I still have problems with checking on the end grain. Thats why, if at all possible, I buy 6 and 8 foot lengths of cedar timbers, and cut the blocks out, 1 at a time as I need them. I lose much less linear length to checking. This becomes especially problematic if you intend to carve hollow deeks, as you don't want to have it check on you so that the checks protrude into the hollow portion. I think it was Andy that suggested coating the interior with epoxy. I've never tried it, but I bet it would work well.
If you ever decide you need a mid winter adventure, and want to drive to Vt to buy cedar timbers, let me know ahead of time and I will send you the name and address of the woman who runs what is probably the largest cedar lumber yard on the east coast. And she lets you pick through the piles....She has acres of cedar timbers on her property.
At the present I have drying under my porch a half dozen 8 foot long 6"x8" cedar timbers I bought a year ago. At the rate I carve, thats probably 4 to 5 years worth of wood.
John