Agree with Weirfan about staying at a hotel.
But a 3-day wedding festival? Screw that. Book a hotel the night before the wedding, attend the wedding and following reception, buy the new couple a wedding gift that they'll never use (like a toaster or blender) and then head back home. Mission accomplished.
I wouldn't spend 3 days celebrating the marriage of a relative, much less a neighbor.
1 day is cool. 3 days is overkill.
Unless you're Owen Wilson or Vince Vaughn. Then just crash that puppy. LOL