My car gets about the same mileage towing my boat or with two kayaks on the roof. I prefer my Zodiac just because it can take 4 divers and go to most any dive site. Without it I would still be kayak diving or using my scooter.
I have two kayaks an Ocean Kayak Scupper Pro TW, that is one of the all time favorites, and a Hobie Revolution with the Mirage pedal drive system (Need to mount my Zodiacs Garmin on it). The Hobie is fast! Of course kelp stops it dead in it's tracks LOL The Hobie can carry double HP100's, and the weight does not phase it. The hard part is getting double back onboard without flipping it a couple of time and it requires two people. I use singles tanks, either HP100's or an HP130, which is what I have for single tanks (Off my boat I just use my doubles). I have a grapnel anchor with 3' of heavy chain, and about 200' of line. I have anchored in 100' of water before, fairly far off Monastery Beach. Awesome dive BTW!
No one I know is deco diving off an unattended boat or kayak. Just like diving off a boat the preferred method is to return to the anchor line. My boat has a thicker anchor line which helps locate it over the thinner kayak line (SMB off the bottom would make the kayak line easier to spot). The Sport Tracker is a nice toy to have for locating the boat, and although not considered by the DIR folks it will allow you to swim up under the boat even if you can not see the boat. Good navigation is the key to boat diving. The underwater GPS system coming is going to be interesting.
I keep a reel with #36 line (Came with 400' of #24) in my scuba gear at all times just in case I ever want to run a line.
One of the key things is to always make sure you can swim to shore in case something does go wrong. Anything inside the Monterey Bay is fairly safe and even off Monastery if you started drifting South you could always come out at Lobos. Of course most of you already know that.
At some point I have been considering getting an EPIRB to attach to my back plate because I do dive the more rugged and less traveled North Coast were the current can be strong.
Eric, if you ever do a free clinic so to speak, let me know. I could bring a couple of kayaks down and walk someone through the process on a dive. Aquarius on Del Monte has a kayak for rent too.
BTW if anyone wants to buy a hand held depth meter PM me.