The big question is; do you need a dinghy? If you don't have access to a live dock to load your gear, the answer to the question is yes, I need a dinghy to bring out passengers and gear. If on the other hand, you have access to a loading dock, I would buy a 9' kayak. It tows beautiful behind your boat and won't slow it down like a dinghy or inflatable and you can hop into it and go exploring or beach combing, or take the dog over to curb. It will fit Kitty cornered into a standard pick-up truck bed. At least mine does, anyway. The answer to getting in and out of the kayak is to have a 15' braid rope on the bow and keep it in the cockpit of the kayak. When you paddle out to the your boat, put the rope around the first lifeline rail and pull the slack out of it and tie it to the Gennie winch. You should be able to hold on to your boat and get right out of the kayak and into the boat. It takes practice and it's doable. You can do the same thing when you come up to a dock. With your kayak tied off to something, you're pushing against the rope and it's up to you to keep the kayak close to the dock or the boat while getting in or out of it. I've been doing it for years. If it can work for me it can work for you. The hot summer months is a good time to practice and get used to your kayak.
Joe