where you need to be: anywhere between lake mile marker 1 (the dam) and mile marker 20ish (town of osage beach). this is "the happening" end of the lake where basically everything you need to have a good time with the guys is located. close to the majority of the bars with boat access (shady gators, horny toad, backwater jacks, dock knockers, etc.) party cove is in the state park off of lake mile 18, you don't want to be that far from here if you plan on going multiple times, unless money is no object, gas on the lake isn't cheap.
things you'll want to do : party cove, there are tons of companies that rent pontoons for hourly or daily rates. I'm betting that you can still find some of these available but look to pay extra since it's memorial day weekend as opposed to just any regular weekend. there will be tons of bar crawls that will take you to a dozen or so different night life spots. I know they do these on fridays and saturdays pretty much all summer and they're relatively cheap ($10 or so + what you spend on booze) there is a decent strip joint (hwy 54 just outside of downtown lake ozark). it isn't fully nude but they're willing to beat the groom and grind all on his face and everything that goes along with bachelor parties.If you're looking for golf, the further you are from the lake, the cheaper it gets. skanks, they're everywhere...
things you don't want to do : worst place ever to drive a boat or car drunk, tons of cops and tons of lake patrol. dont rent PWC's on a weekend like this, the lake is far too choppy with all the traffic that will be out there that it wont even be all that enjoyable.
don't know much about boat or house rental because we have a condo and a boat so I've never done it. the larger hotels/resorts (horny toad for example) have shuttles to get you around, marinas thay contract with, and make it easy for you to get everything you need for a big party weekend in one place. only problem is you'd probably be in a few hotel rooms instead of a condo/house.
this is a good boat rental link
Lake of the Ozarks boat rental, pontoon rental at Lake of the Ozarks, house boat rental Lake of the Ozarks, jet ski rental
hope this helps