My wife and I are around 70 years old and would like to get a kayak (or two) that we can use on some of the lake and rivers in SW Michigan. We are wondering whether a 2-person kayak would be a better choice for us than a single. We're in relatively good shape. We'd like to also be able to take a grandchild (around 6 years old) with us on the lake. We could use some guidance on choosing the right kayak and safety gear we should get. Thanks.
f you have not already done so, rent a few different models to get the feel of them and learn what you like and do not like. My personal preference would be to buy two single kayaks rather than a tandem. The first "must" is a Coast Guard approved PFD. Beyond that, think ten essentials, including a whistle you can attach to your PFD.
I concur with what has been said so far, especially rent first. And Tandem boats are often referred to as "divorce boats" but ymmv. But also, they are almost twice as heavy as a single and not sure how much help the 6 year old will be to offset that
For couples and small child family outings on calm lakes and calm river sections I would consider a 2 person canoe over kayaks. More room to spread out.
For more adventurous explorations (eg rougher water) single kayaks are better assuming you are of similar enthusiasm. You can choose different boats to suit your particular physiques. Tandems a bigger so harder to transport and store and heavier to paddle solo. Could be good in a family setting or if one partner is less enthusiastic but they are a bit more special purpose.
There are various types of kayak depending on your intent. Briefly, Sit ons are good for quick jaunts to the small lake or beach or for a fishing platform in calm waters. Sit ins are best for rougher water and more adventurous expeditions. Inflatables can expand your range while keeping storage and transport easier but there is a range of quality from pool toy to sea capable so know what you are buying.
What safety gear you need depends on where you are going, for how long and when. A PFD and a whistle are the standard items for any boating. For an afternoon by a small lake with other similar users about you may not need much else, beyond the obvious things like appropriate sun protection (water reflects the sun so you need more) hydration and calories (eg a picnic). If you plan longer more remote trips in rougher waters or with motorized traffic you will want to be more fully equipped but you should research what you need specific to that type of trip.