I am going to router all the edges of the wood for a nice feel and stain it. Should I stain before I put it together or after?
I forgot that I rounded over all the corners as well and IMO it's more than worth the trouble. Beyond the obvious desire to protect tender hands, rounded corners will most likely stand up to the elements far longer than sharp splintery ones.
My wife stained it after I had everything else done. This is an outdoor play set with full exposure to the elements and kids doing everything they can imagine to destroy it - not fine woodworking. I don't think it makes any difference at all when you stain it, just do whatever you prefer. Lots of people don't do anything to them.
The other thing I did was used screws everywhere nails were specified (mostly in the steel gussets). This way I haven't had to worry about them backing out.
Should explained the need for a Backhoe with a PTO for an auger based on the need to secure the legs very well.
...and an outbuilding to store said backhoe, and if the outbuilding was just big enough to store the boat as well, that would just be a happy coincidence.