If the OP is looking for somewhere laid back and not far from Orlando, then you can't go wrong with the Gulf Coast in the Tampa Bay Area. We have stayed in Treasure Island a number of times and laid back is what you will certainly get there, as well as things to see/do, amenities and a great beach, though the other beaches and islands in that area are similarly laid back. What's more, that area is no more than 2 hours drive from MCO and easy to get to along Interstate 4, so it's perfectly possible to go straight from MCO to the Gulf Coast or end your holiday there and drive back to MCO late-morning before your flight home - both scenarios we've done before. You might prefer to go there after your reunion in Orlando as it's a nice place to wind down and to have a "holiday" to recover from the parks if you know what I mean!
Someone mentioned the Keys and Key West. It's a great drive and definitely a bucket list-type road trip, so I recommend going there at least once. What I will warn you though is that you're effectively giving up a day to go there as it took us 8 hours to drive from Key West to Orlando 2 years ago including stops as there's long stretches of single lane carriageways along the Keys and we did get stuck behind a lorry or bus or slow driver a number of times. You can halve the driving time if you stop over in the Miami area. Key West in particular is expensive and, at that time of year, it may end up being unbearably hot down there. You could see what flight options exist to avoid an all-day drive (something I might consider doing if I return to Key West in the future having done the drive twice), but bear in mind most airlines limit your luggage allowance due to EYW's short runway so look into that very carefully.