Hello Garmp, I have no personal RV experience with that area (other than being military over at Fort Knox for a few years - no play time at the lake though.)
It looks like the COE built the lake but the campgrounds and land around it are run by the Forest Service - Daniel Boone National Forest. I pulled your lake up on Google Earth where you can see the camp loops and most of the sites, the beaches, some of the topography around the area and location of services. Zilpo is out there while Twin Knobs is a hop, skip and jump into town as well as close to a marina. I didn't check in depth but a lot of Marinas offer tours of the lake or boat rentals if you are into that. The one with easy access will see heavier use.
I then pulled the campgrounds up on Allstays.com and linked to the USFS site for Zilpo http://www.fs.usda.gov/recarea/dbnf/recreation/camping-cabins/recarea/?recid=39322&actid=29
which is open Mid April to Mid October and Twin Knobs which is open Mid March to end of October http://www.fs.usda.gov/recarea/dbnf/recreation/camping-cabins/recarea/?recid=39324&actid=29
. Your pick-up date might determine your campground since you may be too early for Zilpo. You can link to reviews from Allstays also but be aware Allstays simply does an internet search for that name and random stuff occasionally comes up. Make sure you're looking at the right campground. I like reviews from RVparkreviews and tripadvisor but sometimes check other sites that come up. Remember there are all types of RV'ers so a one star review from someone that doesn't want their feet to ever touch soil may not be a negative for you. Some people are comparing the campground to a resort hotel. We compare it to a tent in a primitive area.
If I have a good internet connection I like to look at the Allstays map for the state and zoom into my chosen area. http://www.allstays.com/Campgrounds/Kentucky-campground-map.htm
. Sometimes I find another campground nearby that I prefer. In this instance, I'd be in the forest where you're looking but many people would want the full hook up campgrounds nearby. It just depends on your kind of camping. I also use the map to track along my planned route. Sometimes we don't make it as far as planned and sometimes we decide to just keep on driving. Early spring will narrow your choices though.
Good luck on your planning and enjoy your shakedown. I know when we first hit the road, John needed to know where we would be staying every night for the next few weeks out. But it didn't take us long to start winging it. Many campgrounds have first come first served sites for those without reservations. We call the park and usually get in somewhere. If not, there's always Walmart, Cracker Barrel, Sam's Club, REI, etc. We call ahead, ask if we can stay and they tell us where to park. Not ideal but works as a back up. Many parks have overflow lots also but if it is really cold, you'll be running your furnace and draining your batteries at night then running the generator to recharge during the day... or driving, or plugging in. It's nice to have electric hook ups in cold weather.
We love our Phoenix; it's truly Adventure Anywhere. We were campers also and absolutely love the luxury "camping" we do now. John swears he won't sleep in a tent again (but we carry one just in case we decide to go where RVs can't go.) So life is about to get incredibly sweet for you - ENJOY, ENJOY, ENJOY!!!!