Notre Dame is the best one I've seen but my experience with major FBS is severely limited and I got some serious gold goggles on. A lot of their deal is having an on campus historic stadium on a beautiful, big, and historic campus.
Their tailgating is very simple compared to the big over the top setups you see at NDSU or similar situations. At NDSU, having a camper/bus/etc setup is normal to come across. I wonder if it's sorta a status symbol or something(may just be dedication, I dont know).
The Notre Dame gameday experience is about 90% tradition. They have one of the OG marching bands. They had not changed how they do things for decades until the last couple years when they did their stadium remodel and added a videoboard.
I went to a game in 2015 and it was like walking back in time with how they did things.
Went again last year and it was still like that but with a video board. Heck, even the town looks like something from the 70's or 80's.
It's a trip every fan should try to make at one point or another in their lives but I'm not sure anything can be learned from observing what they do.
It seems like a minor league baseball team going to Fenway or Wrigley and trying to figure out what they are doing right. The answers you find just likely arent going to translate very well.
Big fish like Notre Dame, Alabama, Ohio State, etc. will have a great gameday because that's their identity as a program and university. Any flaws or shortcomings in their way of doing things is glossed over by their brand. They dont need to make things "fun for the family" or do much goofy stuff.
If I had to guess, the best place to emulate for UND might be an hour down the road and a handful of other FCS teams. Not saying to steal what NDSU has done, but I think it might be best to look at schools with similar challenges (relatively small fanbase, limited dollars, geographic isolation).
The NDSU's, Montana's, maybe JMU's of the world could probably at least sort of be emulated I think.