I can't remember what you have for a boat, Craig, but we cruised on a Pearson 26 for two weeks with no problems. It had a plastic cooler under the companionway step for mroe frequent access. We also carried a big steel Coleman cooler that we kept in one of the cockpit lockers. The Coleman is what we kept the meat and other most perishable stuff in. The general rule on keeping things cold and preserving ice is to keep the openings and closings to a minimum. Plan ahead.
Ice: Blocks last longer than cubes. Blocks you make at home last longer than those pseudo-ice pressed snow blocks you buy at the marina or store. Make some at home in a big tupperware or , even better, something the size of a battery box. If you need cubes for drinks, you can either buy bags or chip chunks off the block. I still have a piece of homemade block ice in our ice box into the second week of our cruise.
If you want meat for dinner, freeze it ahead of time. Better yet, freeze it in one of those vacuum bags and put the whole thing in a zip lock. Frozen meat will last a few days in the bottom of your cooler. I also will prepare a meal at home (or buy ginger chicken from the local Thai place), put that in the vacuum pack inside a ziplock and freeze it. Since it's already cooked, it is still good after you've gone through all the raw meat that you packed. That is generally our "Day 5" meal.
Sun showers are great, not sure if you really need one with a freshwater lake. Depending on how refreshingly cold the ocean water is here, I will sometimes take a swim in the ocean with Camp Suds, then rinse under the Sun Shower to conserve fresh water.
We had just a Danforth anchor with some chain and nylon rode. Worked fine.
As someone else mentioned, that Sevylor raft is pretty minimal. I know a guy who tried cruising with one of those and one of the oars broke on the first day. While hitching a ride with others might sound like a solution, that can get a little old after a while. A small dinghy is awful nice to have, not just for going ashore or to another boat, but for exploring whatever anchorage you are in. Oh, they're good for empties and trash storage, too.
I'm not well versed in battery use, but we were fine with two deep cycles (I think?) and regular lights. We did some charging with the motor. I don't think you really need to do a massive changeover to LEDs for a one-week cruise. Do be conservative about lights, but that is pretty easy. Our stereo was one of those yellow Sony boom boxes, so that didn't take up house batts, only C cells.
We always have a lot of bottled water on board. It's easy to get dehydrated. Also, ginger snaps. They are great for both sea sickness and hangovers.
Ditto the idea of doing a weekend aboard as a shakedown.
I like to think we have pocket cruising down to a science (been doing it almost 20 years). Feel free to e-mail if you want.
Best of all, have a blast!!