At first I was thinking, this is a product recommendation question, then I think we can do something useful with this question.
Here is the procedure to follow when setting up Wifi in an Hotel (and probably anywhere else).
Establish your requirement for the service you want to provide to the guests.
a. Do you want them to be able to do basic internet browsing and email, or allow them also to watch on-line movies?
b. How do you want to manage access? Do you want a single password that the front desk give the guests (and therefore anyone who comes to know it can use the wifi in the building near the hotel, etc) or you want to give your guest a tailed password.
c. Do you want to implement such things like redirecting the guests to a promotion page where you detail activities, restaurant menus, etc or just let them on the internet.
d. What's your budget? How much revenue will this bring in? How much can you spend? There is an initial cost of the hardware but there is also a cost for the internet line. I suppose by '42 units' you mean rooms. Most guests will have 2-3 devices (more if it's a family), so 126 clients connected and browsing all the time. You'll need decent bandwidth.
e. Many other possible questions to establish what you want to do.
Look at the various vendors and determine which provide the features you want and fit within what you can afford. Ruckus (I'm a big fan of Ruckus APs and ZoneDirector system), Cisco, Meraki, Aruba, etc. Name at least a couple options.
Review the access point models and discuss with the vendor as needed. You want to pick one that will get you far enough in the future (i.e. has the latest wifi standards, etc). I won't get into saying it needs to do a or g or n, as this will change over time. It suffice to say, it needs to do the right standards for today and near future at least.
Do a site survey.
a. If you can, get an AP from at least two vendors so you can try them in your environment and know you are happy with what you get. But if you can't, then procure 1 AP of the vendor you selected.
b. If you can afford it, get a survey tool like Fluke AirMagnet or other similar tool.
c. Place an AP in one location, test the signal. Repeat, repeat, repeat.
Plan your install. As these are guest rooms, you don't have to worry too much about having too many users connecting to the same AP so you can plan with less dense deployment. It's not like an auditorium where there are large gathering of people in one place (i.e. one AP covers the area but once you have people connecting, you find it won't work).
Buy and install the APs, and your internet line!
Configure and give you to users.
But if you can, hire a firm of professionals on the subject.
You also have to think with support. Who will support the guests? They will have problems connecting and probably 75% of the time it will be user error or something wrong with their iPhone, laptop, etc. And 25% will be something wrong with your setup. But you will need someone that can answer them.