These tournaments are also economic catalysts to some degree, but I think in terms of infrastructure Canada and the USA will be mostly fine already, although I think any event of that magnitude will require infrastructure improvements and adjustments no matter what. Even if it is only for the reason that nothing has been renewed for a long time and additionally, security standards and also quality standards might have risen over time and must now be complied with under a new set of rules and conditions.
I think having Mexico on board is really a good outcome of the whole decision because the countries that are not as rich will benefit from the cooperative effort with nations that are in a better situation. Mexico is also a great soccer nation and I think the mix has been chosen well with the three countries. It sounds tempting to go there and watch one game in each country. It would be an amazing couple of weeks, but getting tickets is probably close to impossible.
The thing is that by far most matches will be played in the US, something like 80% of them, so I'm not sure it would be easy to get one match in each country.
Also you will have to get three different visas, and accommodation in three different countries.
I will probably be a very expensive way of watching the tournament. Fun of course, but expensive.