Be sure to cover your wood with some sort of protectant. Fiberglass resin thinned with acetone does a great job of sealing. Rivets would work well...or nuts and bolts. Not a big fan of screws myself. Be sure to get stainless hardware...then it doesn't rust anymore. Most hardware stores will have stainless stuff.
As far as the cracks...yeah you need to do something or the cracks will worsen. JB Weld is good...there are so many epoxies and fixing kits out there you really can't go wrong with any of them. There are some now that set up so quick and hard you better be quick with getting them on there. The holes will be so the epoxy has something to grab to. Best thing is to have it welded with a MIG or TIG or maybe oxy/ace welding. Probably just one of the good epoxies though.
Good luck!!!
"But if serving the Lord seems undesirable to you, then choose for yourselves this day whom you will serve, whether the gods your ancestors served beyond the Euphrates, or the gods of the Amorites, in whose land you are living. But as for me and my household, we will serve the Lord.” Joshua 25:15