Edit: Apparently people aren't as familiar with how this game works as I assumed. Mario Golf World Tour has simultaneous online play, but it also lets you host your own tournaments to play asynchronously.
I set up a tournament for our forum. It'll be up until May 9th (Friday) around midnight, and you can play whenever you want and however many times you want.
Mario Golf's UI is incredibly unintuitive, so here's how to enter the tourney:
Quick Round > Tournaments > Private Tournament > Search by Code
The code is
If there's enough interest, I'll update this post with a new tournament each week, and it'll be fun and awesome.