I'm sure you'll get lots of feedback on these questions.

My comments:

"No refrigeration, so blocks of ice." If you have a well insulated cooler you'll be fine, so long as you can refresh the ice every 2-3 days. (Hint - Never put anything in a cooler that isn't already cold).

"Tankage, we have 25 freshwater, 25 holding". If you dry-flush the pee and minimize flush water a couple should be good for at least 3 days before you need a pump-out. If you short-shower and wash dishes with lake water then rinse with tank water, a couple can use under 10 gallons a day. If you shower with lake water you can cut that in half. Figure 2-3 gallons a day for drinking/cooking/coffee for a couple.

"We have a cold water shower, but we also have a lake full of fresh water to dive into." Think solar -- the Sun-Shower bags work well, as do hand-pump garden sprayers painted black.

"12v power, right now we have a month old group 31 house deep cycle and a week old group 24 DC, no genset, solar or wind. Our power needs would only be lights and stereo, we have no A/C, TV, or inverter right now." Save your house bank for the anchor light and user flashlights or lanterns. Better yet, get a Bebi Owl LED anchor light. Don't bridge the start battery to the house bank unless the engine is charging. use the radio if you want, but if you don't have a battery monitor use a voltmeter on the house bank and don't get it get lower than 11.9 volts (that would be about 40% charge) or you'll shorten its life.

"We do not have a formal dink, we do have an inflatable Sevylor 6 person raft with a nylon cover w/oars for power." Whatever works. If you're buddy-cruising you can always hitch a ride with friends.